Assertion in ModuleLoader

After updating to the latest revision I'm getting this assertion, so the project could not be resolved:
ERROR: /home/kds/src/qbs/src/lib/corelib/language/moduleloader.cpp:1340 ASSERT: found

I tried commenting out parts of the project and finally got it resolved when commented all cpp.includeDirectories and cpp.defines inside Export items. Further investigation showed that I can do that in one particular product only, but that product has nothing special. It exports properties as well as the other products do.

Tried to debug and noted v->definingItem()>scope()>scope() points to the same file in the project as depMod.item->prototype(), but they are different instances (have different addresses), so the lookup fails.

Unfortunately I didn't succeed in making a minimal example project to reproduce the bug. Tried different combinations of Product, Export and Group and everything worked as expected