The latest versions 2.11.0 and 1.34.0 don't support using freezegun in unit tests, e.g., in conjunction with google-cloud-datastore. It seems the following merge broke it:
fix: Major refactoring of Polling, Retry and Timeout logic
#462

Version 2.10.2, which is the last version before that merge, works fine.

Do you need more info?