Reproduction case:

from __future__ import annotations

import attr

@attr.define()
class A:
  n: int

@attr.define()
class B(A):
  pass

attr.resolve_types(A)
attr.resolve_types(B)

print(attr.fields(B))

I believe this is because B is somehow inheriting A's __attrs_types_resolved__, even though it gets set later -- which means that it never had its types resolved, but it thinks it has.

This came up when I was using cattrs (I raised an issue there about a trouble I had debugging too :^), which means I do not control the resolution order of types without applying a attr.resolve_types decorator to every class (which might not work -- I'm not sure all my class declarations are in order either...)