Type inconsistency when loading .bzl from different cells

I've created a repo (https://github.com/yxdai-nju/buck2-cross-cell-bzl-load-issue) demonstrating the problem. Loading the same .bzl from different cells seems to result in incompatible type definitions, despite having identical type names.

Start with the linked reproduction repository and trace the .bzl loads across the different cells, comparing the resulting type definitions. Reproduce the behavior, then identify what should make identical type names compatible across cells; done means the reproduction no longer reports incompatible types.

Written by the indexing model from the issue text.