Weird, Inconsistent Behavior with WCF and TypeMock

I'm currently running into an issue where I'm trying to test a WCF behavior that implement IErrorProvider. In the HandleError() method, the client has created a class that requires us to call a static method. So I'm trying to hook that method call via Fake.StaticMethods. However, I keep getting inconsistent behavior when I run the tests. I've created a project that I'd be more than willing to send to the TypeMock folks to demonstrate the issue.

Well, the sample project I created doesn't quite give the same problem. My tests in the sample project will succeed the first time, and then fail every time after that. In the "real" project code (that I can't ship to anyone) the test succeeds but VsTestHost.exe will crash with a System.ServiceModel.Diagnostics.CallbackException. But to make a long story short, there's a fair amount more going on in the "real" code than my test project, but I'm guessing by looking at the test project that might help out with the real issue.

Any help/ideas/WAGs would be appreciated :)

Thanks,
Jason