Hi, thanks for reporting this problem.
The issue appears to be related to NCrunch's instrumentation of the assembly containing this method. For some reason, the instrumentation is dropping a critical piece of metadata (namely, the '= true') from the parameter. Methods calling 'HasValue' will work normally if they are inside the same assembly as this method, although they fail if they call it across assembly boundaries.
I'll see if I can get a fix for this included in 1.43, which is due out within the next few days. Thanks again for reporting the issue and providing the clear steps to reproduce it.
Cheers,
Remco