Thanks for the pointers.
I have cleared the cache for all the machines running the console tool, and cleared the grid node machines working folders and set the option to not instrument. It doesn't seem to make any difference. This is the log from the build server (up to the point of the error):
[14:43:15][Step 17/27] NCrunch Console Tool v3.26.0.4
[14:43:15][Step 17/27] Copyright ¸ 2010-2018 Remco Software Ltd
[14:43:15][Step 17/27] Usage of this tool is permitted only under the terms described in License.rtf
[14:43:15][Step 17/27]
[14:43:15][Step 17/27]
[14:43:15][Step 17/27]
[14:43:15][Step 17/27] This product is licensed to Applied Systems, Inc. (support/maintenance expires 15-May-2019)
[14:43:15][Step 17/27]
[14:43:15][Step 17/27] [?-1] Initialising UI Services
[14:43:16][Step 17/27] [?-1] NCrunch Services Initialised
[14:43:16][Step 17/27] [Core-15] Console tool is using engine mode: [Undetermined]
[14:43:16][Step 17/27] [Core-15] Beginning end-to-end run of solution using tools from VS version 'VS2019'
[14:43:16][Step 17/27] [Core-15] Now dumping raw settings. Note that not all of these settings are used by the console tool:
[14:43:16][Step 17/27] [Core-15] Check for updates = 'True'
[14:43:16][Step 17/27] [Core-15] Project config file storage path = ''
[14:43:16][Step 17/27] [Core-15] Custom environment variables = 'nCrunch.Compiler.CustomVariable[]'
[14:43:16][Step 17/27] [Core-15] Tests to execute on this machine = 'True'
[14:43:16][Step 17/27] [Core-15] Track engine performance = 'False'
[14:43:16][Step 17/27] [Core-15] Log to output window = 'False'
[14:43:16][Step 17/27] [Core-15] Impact detection mode = 'CompareIL'
[14:43:16][Step 17/27] [Core-15] Engine hosting strategy = 'HostInsideIDE'
[14:43:16][Step 17/27] [Core-15] Pipeline optimisation priority = 'Throughput'
[14:43:16][Step 17/27] [Core-15] CPU cores assigned to Visual Studio = '4,5,6,7'
[14:43:16][Step 17/27] [Core-15] CPU cores assigned to NCrunch = '0,1,2,3'
[14:43:16][Step 17/27] [Core-15] Auto adjust clashing marker colours = 'True'
[14:43:16][Step 17/27] [Core-15] Marker colour for lines with no coverage = 'a255, r0, g0, b0'
[14:43:16][Step 17/27] [Core-15] Marker colour for lines with a slower execution time = 'a255, r255, g255, b0'
[14:43:16][Step 17/27] [Core-15] Marker colour for lines with passing coverage = 'a255, r0, g128, b0'
[14:43:16][Step 17/27] [Core-15] Marker colour for lines with failing coverage = 'a255, r255, g0, b0'
[14:43:16][Step 17/27] [Core-15] Tool window colours = '(Use default IDE colours)'
[14:43:16][Step 17/27] [Core-15] Text output font = 'Courier New, 8.25pt, 0'
[14:43:16][Step 17/27] [Core-15] Coverage marker style = 'Circle'
[14:43:16][Step 17/27] [Core-15] Marker performance display sensitivity = '100'
[14:43:16][Step 17/27] [Core-15] Marker performance aggregation type = 'Average'
[14:43:16][Step 17/27] [Core-15] Inner circle colour = 'a255, r255, g255, b255'
[14:43:16][Step 17/27] [Core-15] Outer circle colour on build failure = 'a255, r186, g115, b0'
[14:43:16][Step 17/27] [Core-15] Outer circle colour on test failure = 'a255, r255, g0, b0'
[14:43:16][Step 17/27] [Core-15] Outer circle colour while initialising = 'a255, r0, g0, b255'
[14:43:16][Step 17/27] [Core-15] Outer circle colour when no failures exist = 'a255, r0, g128, b25'
[14:43:16][Step 17/27] [Core-15] Text colour = 'a255, r0, g0, b255'
[14:43:16][Step 17/27] [Core-15] Text colour when tests are failing = 'a255, r255, g0, b0'
[14:43:16][Step 17/27] [Core-15] Text colour when a build has recently failed = 'a90, r0, g0, b0'
[14:43:16][Step 17/27] [Core-15] Text colour when a build has failed = 'a255, r0, g0, b0'
[14:43:16][Step 17/27] [Core-15] Text colour when tests have recently failed = 'a90, r0, g0, b0'
[14:43:16][Step 17/27] [Core-15] Text colour when tests are queued = 'a255, r0, g80, b0'
[14:43:16][Step 17/27] [Core-15] Orbiter colour for build tasks = 'a255, r255, g255, b255'
[14:43:16][Step 17/27] [Core-15] Orbiter colour for analysis tasks = 'a255, r255, g255, b255'
[14:43:16][Step 17/27] [Core-15] Orbiter colour for test tasks = 'a255, r255, g255, b255'
[14:43:16][Step 17/27] [Core-15] Additional files to include = ''
[14:43:16][Step 17/27] [Core-15] Additional files for grid processing = ''
[14:43:16][Step 17/27] [Core-15] Allow parallel test execution = 'True'
[14:43:16][Step 17/27] [Core-15] Infer project references using assembly names = 'False'
[14:43:16][Step 17/27] [Core-15] Allow tests to run in parallel with themselves = 'True'
[14:43:16][Step 17/27] [Core-15] Fast lane threads = '0'
[14:43:16][Step 17/27] [Core-15] Fast lane threshold (in ms) = '10000'
[14:43:16][Step 17/27] [Core-15] Sliding build delay (in ms) = '0'
[14:43:16][Step 17/27] [Core-15] Grid reconnection delay (in seconds) = '10'
[14:43:16][Step 17/27] [Core-15] Share tests ignored by NCrunch = 'True'
[14:43:16][Step 17/27] [Core-15] Share metrics excluded by NCrunch = 'True'
[14:43:16][Step 17/27] [Core-15] Tests to execute automatically = 'True'
[14:43:16][Step 17/27] [Core-15] Show coverage for tests = 'True'
[14:43:16][Step 17/27] [Core-15] Show metrics for tests = 'True'
[14:43:16][Step 17/27] [Core-15] Automatically pin newly discovered tests = 'False'
[14:43:16][Step 17/27] [Core-15] Only consider tests 'Out of date' if they are 'Impacted' = 'False'
[14:43:16][Step 17/27] [Core-15] Required capabilities = 'System.String[]'
[14:43:16][Step 17/27] [Core-15] Build priority = '1000'
[14:43:16][Step 17/27] [Core-15] Auto-detect NuGet build dependencies = 'True'
[14:43:16][Step 17/27] [Core-15] Ignore this component completely = 'False'
[14:43:16][Step 17/27] [Core-15] Files excluded from auto build = 'nCrunch.Common.IO.FileSpec[]'
[14:43:16][Step 17/27] [Core-15] Max number of processing threads = '0'
[14:43:16][Step 17/27] [Core-15] NCrunch cache storage path = 'C:\NCrunchCacheFiles'
[14:43:16][Step 17/27] [Core-15] Terminate test runner tasks when all test execution is complete = 'False'
[14:43:16][Step 17/27] [Core-15] Workspace base path = ''
[14:43:16][Step 17/27] [Core-15] Build process memory limit (in bytes) = '125000000'
[14:43:16][Step 17/27] [Core-15] Test process memory limit (in bytes) = '0'
[14:43:16][Step 17/27] [Core-15] Max number of test runner processes to pool = '1'
[14:43:16][Step 17/27] [Core-15] Log verbosity = 'Low'
[14:43:16][Step 17/27] [Core-15] Capabilities of this computer = 'LocalRun'
[14:43:16][Step 17/27] [Core-15] LocalRun
[14:43:16][Step 17/27] [Core-15] Custom build properties = 'nCrunch.Compiler.CustomVariable[]'
[14:43:16][Step 17/27] [Core-15] Instrument output assembly = 'False'
[14:43:16][Step 17/27] [Core-15] Copy referenced assemblies to workspace = 'False'
[14:43:16][Step 17/27] [Core-15] Run pre-build events = 'False'
[14:43:16][Step 17/27] [Core-15] Run post-build events = 'False'
[14:43:16][Step 17/27] [Core-15] Prevent signing of output assembly = 'False'
[14:43:16][Step 17/27] [Core-15] Track file dependencies = 'True'
[14:43:16][Step 17/27] [Core-15] Analyse line execution times = 'True'
[14:43:16][Step 17/27] [Core-15] Detect stack overflow = 'True'
[14:43:16][Step 17/27] [Core-15] Pre-load all assembly references into test environment = 'False'
[14:43:16][Step 17/27] [Core-15] Consider inconclusive tests as passing = 'False'
[14:43:16][Step 17/27] [Core-15] Include static references in workspace = 'True'
[14:43:16][Step 17/27] [Core-15] Use build platform = ''
[14:43:16][Step 17/27] [Core-15] Use build configuration = ''
[14:43:16][Step 17/27] [Core-15] Build process CPU architecture = 'x86'
[14:43:16][Step 17/27] [Core-15] Proxy process file path = ''
[14:43:16][Step 17/27] [Core-15] Use CPU architecture = 'AutoDetect'
[14:43:16][Step 17/27] [Core-15] Default test timeout = '60000'
[14:43:16][Step 17/27] [Core-15] Allow code analysis = 'False'
[14:43:16][Step 17/27] [Core-15] Allow dynamic code contract checking = 'True'
[14:43:16][Step 17/27] [Core-15] Allow static code contract checking = 'False'
[14:43:16][Step 17/27] [Core-15] Framework utilisation type for Gallio/Xunit v1 = 'UseStaticAnalysis'
[14:43:16][Step 17/27] [Core-15] Framework utilisation type for MSpec = 'UseStaticAnalysis'
[14:43:16][Step 17/27] [Core-15] Framework utilisation type for MSTest = 'UseStaticAnalysis'
[14:43:16][Step 17/27] [Core-15] MSTest thread apartment state = 'STA'
[14:43:16][Step 17/27] [Core-15] Framework utilisation type for NUnit v2 = 'UseDynamicAnalysis'
[14:43:16][Step 17/27] [Core-15] NUnit v3+ Enabled = 'True'
[14:43:16][Step 17/27] [Core-15] XUnit v2+ Enabled = 'True'
[14:43:17][Step 17/27] [Core-15] Loading internal NCrunch modules
[14:43:17][Step 17/27] [Core-15] Loading module: AspNetMvcTestHostModule
[14:43:17][Step 17/27] [Core-15] Loading module: CodeAnalysisModule
[14:43:17][Step 17/27] [Core-15] Loading module: CodeContractsModule
[14:43:17][Step 17/27] [Core-15] Loading module: MSFakesModule
[14:43:17][Step 17/27] [Core-15] Loading module: MvcBuildModule
[14:43:17][Step 17/27] [Core-15] Loading module: SpecFlowModule
[14:43:17][Step 17/27] [Core-15] Loading module: StyleCopModule
[14:43:17][Step 17/27] [Core-15] Loading external NCrunch modules
[14:43:17][Step 17/27] [Core-15] Loading module: C:\Program Files (x86)\Remco Software\NCrunch Console Tool\Modules\Gallio\nCrunch.Module.Gallio.crunchmodule
[14:43:17][Step 17/27] [Core-15] Loading module: C:\Program Files (x86)\Remco Software\NCrunch Console Tool\Modules\MSpec\nCrunch.Module.MSpec.crunchmodule
[14:43:17][Step 17/27] [Core-15] Loading module: C:\Program Files (x86)\Remco Software\NCrunch Console Tool\Modules\MSTest\nCrunch.Module.MSTest.crunchmodule
[14:43:17][Step 17/27] [Core-15] Loading module: C:\Program Files (x86)\Remco Software\NCrunch Console Tool\Modules\NUnit\nCrunch.Module.NUnit.crunchmodule
[14:43:17][Step 17/27] [Core-15] Loading module: C:\Program Files (x86)\Remco Software\NCrunch Console Tool\Modules\NUnit3\nCrunch.Module.NUnit3.crunchmodule
[14:43:17][Step 17/27] [Core-15] Loading module: C:\Program Files (x86)\Remco Software\NCrunch Console Tool\Modules\XUnit2\nCrunch.Module.XUnit2.crunchmodule
[14:43:20][Step 17/27] [Core-15] Framework description manager has loaded data for 6 test frameworks
[14:43:21][Step 17/27] [InitialisationQueueTask-60] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\PolicyLine.Definition.csproj' because package restore mode is disabled
[14:43:21][Step 17/27] [InitialisationQueueTask-60] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\PolicyLine.Definition.csproj
[14:43:25][Step 17/27] [InitialisationQueueTask-119] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Service\PolicyLine.Definition.Service.csproj' because package restore mode is disabled
[14:43:25][Step 17/27] [InitialisationQueueTask-119] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Service\PolicyLine.Definition.Service.csproj
[14:43:26][Step 17/27] [InitialisationQueueTask-98] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Tests\Specifications\PolicyLine.Definition.Tests.Specifications.csproj' because package restore mode is disabled
[14:43:26][Step 17/27] [InitialisationQueueTask-98] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Tests\Specifications\PolicyLine.Definition.Tests.Specifications.csproj
[14:43:27][Step 17/27] [InitialisationQueueTask-178] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\DbUp\PolicyLine.Definition.DbUp.csproj' because package restore mode is disabled
[14:43:27][Step 17/27] [InitialisationQueueTask-178] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\DbUp\PolicyLine.Definition.DbUp.csproj
[14:43:27][Step 17/27] [InitialisationQueueTask-80] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\EsUp\PolicyLine.Definition.EsUp.csproj' because package restore mode is disabled
[14:43:27][Step 17/27] [InitialisationQueueTask-80] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\EsUp\PolicyLine.Definition.EsUp.csproj
[14:43:27][Step 17/27] [InitialisationQueueTask-111] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Events\PolicyLine.Events.csproj' because package restore mode is disabled
[14:43:27][Step 17/27] [InitialisationQueueTask-111] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Events\PolicyLine.Events.csproj
[14:43:28][Step 17/27] [InitialisationQueueTask-31] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\RiskConversion\PolicyLine.RiskConversion.csproj' because package restore mode is disabled
[14:43:28][Step 17/27] [InitialisationQueueTask-31] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\RiskConversion\PolicyLine.RiskConversion.csproj
[14:43:28][Step 17/27] [InitialisationQueueTask-29] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Tests\Load\PolicyLine.Definition.Tests.Load.csproj' because package restore mode is disabled
[14:43:28][Step 17/27] [InitialisationQueueTask-110] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\RiskConversion\Tests\PolicyLine.RiskConversion.Tests.csproj' because package restore mode is disabled
[14:43:28][Step 17/27] [InitialisationQueueTask-110] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\RiskConversion\Tests\PolicyLine.RiskConversion.Tests.csproj
[14:43:29][Step 17/27] [InitialisationQueueTask-192] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Web\Service\PolicyLine.Definition.Web.Service.csproj' because package restore mode is disabled
[14:43:29][Step 17/27] [InitialisationQueueTask-192] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Web\Service\PolicyLine.Definition.Web.Service.csproj
[14:43:29][Step 17/27] [InitialisationQueueTask-37] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Queries\PolicyLine.Definition.Queries.csproj' because package restore mode is disabled
[14:43:29][Step 17/27] [InitialisationQueueTask-37] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Queries\PolicyLine.Definition.Queries.csproj
[14:43:30][Step 17/27] [InitialisationQueueTask-32] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Queries\Service\PolicyLine.Definition.Queries.Service.csproj' because package restore mode is disabled
[14:43:30][Step 17/27] [InitialisationQueueTask-32] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Queries\Service\PolicyLine.Definition.Queries.Service.csproj
[14:43:30][Step 17/27] [InitialisationQueueTask-17] Not restoring NuGet packages for 'D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Infrastructure\PolicyLine.Definition.Infrastructure.csproj' because package restore mode is disabled
[14:43:30][Step 17/27] [InitialisationQueueTask-17] Loading project: D:\BuildAgent-02\work\7673952c0788e6a\MainProject\PolicyLine\Definition\Infrastructure\PolicyLine.Definition.Infrastructure.csproj
[14:43:30][Step 17/27] [Core-15] All projects have been loaded
[14:43:31][Step 17/27] [Core-15] Queuing 765 tests for passive execution
[14:43:31][Step 17/27] [Core-15] Queuing 189 tests for passive execution
[14:43:32][Step 17/27] [Core-15] Queuing 765 tests for passive execution
[14:43:32][Step 17/27] [Core-15] Queuing 189 tests for passive execution
[14:43:32][Step 17/27] [Core-15] Connection established with remote grid node at uk-devngn01
[14:43:32][Step 17/27] [Core-15] Connection established with remote grid node at uk-devngn03
[14:43:32][Step 17/27] [Core-15] Connection established with remote grid node at uk-devba06
[14:43:32][Step 17/27] [Core-15] Connection established with remote grid node at uk-devngn02
[14:43:32][Step 17/27] [Core-276] Queuing 765 tests for passive execution
[14:43:32][Step 17/27] [Core-276] Queuing 189 tests for passive execution
[14:43:35][Step 17/27] [Core-109] Sending processing instructions to node uk-devngn02 for 4 tasks
[14:43:39][Step 17/27] [Core-94] Grid node uk-devngn02 reports task completed: [LocalBuildTask: [SnapshotComponent: PolicyLine.Definition.DbUp, 3, 41746693], ProcessingSucceeded, UK-DEVNGN02, e1b0b5da-1bae-469a-9cd4-3414318b82e3]
[14:43:40][Step 17/27] NCrunch build: PolicyLine.Definition.DbUp
[14:43:40][Step 17/27] [Core-94] Grid node uk-devngn02 reports task completed: [LocalBuildTask: [SnapshotComponent: PolicyLine.Definition.Infrastructure, 11, 27429540], ProcessingSucceeded, UK-DEVNGN02, aa0fb464-aa62-47e2-9c12-684737bb1756]
[14:43:40][Step 17/27] NCrunch build: PolicyLine.Definition.Infrastructure
[14:43:40][Step 17/27] [Core-187] Grid node uk-devngn02 reports task completed: [LocalBuildTask: [SnapshotComponent: PolicyLine.Events, 5, 54581537], ProcessingSucceeded, UK-DEVNGN02, 9a3f7ecf-5ad2-4996-9da8-c8f33e07b60a]
[14:43:40][Step 17/27] NCrunch build: PolicyLine.Events
[14:43:40][Step 17/27] [Core-187] Sending processing instructions to node uk-devngn02 for 2 tasks
[14:43:42][Step 17/27] [Core-81] Grid node uk-devngn02 reports task completed: [LocalBuildTask: [SnapshotComponent: PolicyLine.RiskConversion, 6, 1669168], ProcessingSucceeded, UK-DEVNGN02, da455b02-20c5-419e-b28a-4ba666a3384a]
[14:43:42][Step 17/27] NCrunch build: PolicyLine.RiskConversion
[14:43:42][Step 17/27] [Core-107] Grid node uk-devngn02 reports task completed: [LocalBuildTask: [SnapshotComponent: PolicyLine.Definition, 0, 58139041], ProcessingSucceeded, UK-DEVNGN02, 8ad1a8f2-b225-440b-adda-0cb996bd0d5e]
[14:43:43][Step 17/27] NCrunch build: PolicyLine.Definition
[14:43:43][Step 17/27] [Core-107] Sending processing instructions to node uk-devngn02 for 2 tasks
[14:43:45][Step 17/27] [Core-183] Grid node uk-devngn02 reports task completed: [LocalBuildTask: [SnapshotComponent: PolicyLine.Definition.Queries, 9, 38089639], ProcessingSucceeded, UK-DEVNGN02, a0b4b161-37fe-4a22-8428-7266f8e4c606]
[14:43:45][Step 17/27] NCrunch build: PolicyLine.Definition.Queries
[14:43:45][Step 17/27] [Core-183] Sending processing instructions to node uk-devngn02 for 2 tasks
[14:43:45][Step 17/27] [Core-102] Grid node uk-devngn02 reports task completed: [LocalBuildTask: [SnapshotComponent: PolicyLine.Definition.Service, 1, 20941281], ProcessingSucceeded, UK-DEVNGN02, 5b89b2ec-1e6d-43e2-819c-4b0d56af3022]
[14:43:45][Step 17/27] NCrunch build: PolicyLine.Definition.Service
[14:43:45][Step 17/27] [Core-11] Grid node uk-devngn02 reports task completed: [LocalBuildTask: [SnapshotComponent: PolicyLine.Definition.EsUp, 4, 19005986], ProcessingSucceeded, UK-DEVNGN02, 9e98b704-bd53-4b0b-b3f4-27d24f0b6ab1]
[14:43:45][Step 17/27] NCrunch build: PolicyLine.Definition.EsUp
[14:43:46][Step 17/27] [Core-81] Grid node uk-devngn02 reports task completed: [LocalBuildTask: [SnapshotComponent: PolicyLine.Definition.Queries.Service, 10, 59907435], ProcessingSucceeded, UK-DEVNGN02, d22666a4-b1a7-4e05-a8e7-2e21e2c9849f]
[14:43:46][Step 17/27] NCrunch build: PolicyLine.Definition.Queries.Service
[14:43:50][Step 17/27] [Core-118] Sending processing instructions to node uk-devngn03 for 4 tasks
[14:43:51][Step 17/27] [Core-283] Grid node uk-devngn02 reports task completed: [LocalBuildTask: [SnapshotComponent: PolicyLine.Definition.Web.Service, 8, 41387062], ProcessingSucceeded, UK-DEVNGN02, daa27a72-250a-47c7-a02a-d731bd8c831e]
[14:43:51][Step 17/27] NCrunch build: PolicyLine.Definition.Web.Service
[14:43:51][Step 17/27] [Core-283] Sending processing instructions to node uk-devngn02 for 1 tasks
[14:43:52][Step 17/27] [Core-52] Sending processing instructions to node uk-devba06 for 4 tasks
[14:43:54][Step 17/27] [Core-174] Grid node uk-devngn02 reports task completed: [LocalBuildTask: [SnapshotComponent: PolicyLine.Definition.Tests.Specifications, 2, 5804477], ProcessingSucceeded, UK-DEVNGN02, 8d24a372-d7f0-4ad6-b77d-51d39f8260c5]
[14:43:54][Step 17/27] NCrunch build: PolicyLine.Definition.Tests.Specifications
[14:43:54][Step 17/27] [Core-174] ERROR (Internal): System.IndexOutOfRangeException: Index was outside the bounds of the array.
[14:43:54][Step 17/27] [Core-174] at nCrunch.Client.Model.CodeCoverage.Indexes.CoverageIndex`1.MergeNewLineCoverageDataIntoIndexReturningChangedCodeMembers(ModelTest test, ComponentUniqueName componentUniqueName, ICoveragePointIterator`1 newCoveragePoints)
[14:43:54][Step 17/27] [Core-174] at nCrunch.Client.Model.CodeCoverage.CoverageDatabase.MergeNewEntryCoverageDataIntoDatabaseReturningChangedCodeMembers(ModelTest test, ComponentUniqueName componentUniqueName, ICoveragePointIterator`1 newCoveragePoints)
[14:43:54]
[Step 17/27] [Core-174] at nCrunch.Client.Model.CodeCoverage.CodeCoverageMerger. (TestLocationsRegisteredEvent )
[14:43:54][Step 17/27] ##teamcity[buildProblem description='Index was outside the bounds of the array. - System.IndexOutOfRangeException: Index was outside the bounds of the array.|r|n at nCrunch.Client.Model.CodeCoverage.Indexes.CoverageIndex`1.MergeNewLineCoverageDataIntoIndexReturningChangedCodeMembers(ModelTest test, ComponentUniqueName componentUniqueName, ICoveragePointIterator`1 newCoveragePoints)|r|n at nCrunch.Client.Model.CodeCoverage.CoverageDatabase.MergeNewEntryCoverageDataIntoDatabaseReturningChangedCodeMembers(ModelTest test, ComponentUniqueName componentUniqueName, ICoveragePointIterator`1 newCoveragePoints)|r|n at nCrunch.Client.Model.CodeCoverage.CodeCoverageMerger. (TestLocationsRegisteredEvent )' timestamp='2019-09-20T14:43:54.564+0100']
[14:43:54][Step 17/27] [Core-174] Queuing 765 tests for passive execution
If I stop the machine which has the grid node which looks to have caused the issue (uk-devngn02 above) then the error seems to switch to a different machine.
Any ideas?