Hello,

The attached simple test calls free functions with bad smob_tag.
I see the same stuff with 2.2.0
There are no errors using the stable 2.0.11 version.

my system is:
Linux linux8 4.10.0-19-generic #21-Ubuntu SMP Thu Apr 6 17:04:57 UTC
2017 x86_64 x86_64 x86_64 GNU/Linux