I'll take a look at your patch.

The root problem is that the wrapper functions will return NULL if they are fed the wrong number of arguments (i.e. the int.__add__ wrapper expects exactly two arguments but the ** call provides three) -- you will see a similar result if int.__neg__ or int.__invert__ are assigned to __add__.   It looks like an upstream step is seeing the NULL and deciding that it needs to look to skip the given method call and instead try the base the class.

Am lowering the priority because there is no good use case for deliberate argument mismatches in the override.  Am leaving the bug open because we want the appropriate error message to surface.