Inverse Heisenbug - Unit test fails only when debugger is attached

Question

I recently fixed a defect in our product, the symptom of which was an access violation caused by accessing a dangling pointer.

For good practice I added a unit test

Answer 1

I ran into this years ago in reverse: The problem was only occurring when the debugger was not attached.

It turned out the code was corrupting the stack-frame of the previous method activation and using the debugger introduced an intermediate stack-frame.

You possibly have a similar situation.