I did not yet run MSBuild.EXE, I did come a little bit closer to the issue/ a solution.
I can replicate the issue by using the rename functionality in Rider.
I managed to replicate this in a new solution, where just creating a class,
namespace ClassLibrary1
{
public class DeSyncTest : IDesyncTest
{
}
}
And an interface in a seperate file
namespace ClassLibrary1
{
public interface IDesyncTest
{
}
}
If I rename the interface in the command using the 'Rename', I get the error. In the test project it doesn't always happen (sometimes I can see it happen and then it fixes itself again, sometimes it happens and it does not fix itself, until I make an edit in the file that can't be found or restart Rider).
In the main project I am using, it breaks more consistently. If I look in the workspace I can indeed see that the rename did not properly happen in the workspace, so the MSBuild would probably also fail.
I made another bug report: 'Post 3497'
I recreated the issue, I got the error, checked the workspace which did not contain the rename. I tried reloading the project which doesn't fix the issue, but in the newly made project resetting the NCRunch project seems to help.
Also when I open submit a bug report it fixes the issue most of the time, although for this bug report it didn't.