At what level? I just had this exact thing, and “fixed” it. So if it’s at level 3 that it bugs out I might be able to help you.
To debug, I had to make very sure that I’m launching the pluginval version that I just (Debug target!) compiled with Xcode. Then, compile my plugin from Xcode as well, then attach to pluginval process, make sure pluginval points to your just compiled build, make sure pluginval Options→Validate in-process is turned on, then run the test. If I forgot one of these steps I would always land in some assembler code.