Provided you're using .NET Core 2.2 or above, then there shouldn't be a known issue with these tests. However, the architecture of this library and the manner of its development has made it hard for us to integrate with it, so it wouldn't surprise me if there is an unconsidered edge case or a version that has changed from the known state.
The code trying to resolve the .json file isn't actually NCrunch - it'll be something in the .NET runtime or associated libraries. Normally this file should be present inside the build output directory of your test project if the 'Copy referenced assemblies to workspace' is turned on.
Is there any chance you can reproduce this problem with a small self contained sample solution? If you can share such a solution with me via the
contact form, I'll be happy to take a closer look and provide further advice or a fix.