If you're using PyMelloc, as your allocator, you can wind up with memory that has been freed back to Python. And we won't necessarily know what objects were responsible for that. So in memory leaks mode, you either want to trace the Python allocators as well so that we can see when Python objects are freed,. or you can run with a different allocator, just Malick. You can tell Python to disable thePyMelloc allocator entirely and just whenever it needs any memory to always just call the system Malick.