There was just a pull request merged into Python 3.12 to change how types.get_original_bases() behaves for generic types whose bases have no type arguments.

• Issue: Odd types.get_original_bases() behavior for classes with generic bases but no type arguments cpython#107576
• Pull Request: gh-107576: Ensure __orig_bases__ are our own in get_original_bases cpython#107584

The TL;DR is that types.get_original_bases(cls) should only use cls's own __orig_bases__, not an ancestor type's via MRO, and should fall back to cls.__bases__ otherwise.