Looks like the `inject(NgZone)` added here on #3586 are causing these issues for compat:   Here are the lines in the repo: https://github.com/angular/angularfire/blame/main/src/compat/firestore/firestore.ts#L200 https://github.com/angular/angularfire/blame/main/src/compat/firestore/firestore.ts#L230