After a lot of debugging, it looks like this is the line that is the bug - instead of catching a google.auth.exceptions.DefaultCredentialsError and passing, its trying to catch an AttributeError:

This is crashing my requests to get a user via a Rest API using the library on a local environment with the emulator running but no local credentials installed/local SDK.

Please make sure tests for using the emulator assume no credentials are on the machine or they will break CI/CD pipelines. Any work arounds before a fix is released appreciated!