What happens if I remove reference to default FirebaseAuth instance during runtime?

[comatory]

I have a couple of Firebase services that need to be started up only after user signs in. I'm using custom sign in provider.

For me this means

1. Initializing Firebase with await Firebase.initializeApp() when my application starts.
2. Wait for user to sign-in.
3. After succesful sign-in I create FirebaseAuth instance by doing _auth = FirebaseAuth.instance
4. I do the same for FirebaseFirestore with _store = FirebaseFirestore.instance

I'm trying to hunt down a bug where if I open my application after some time, I'm not receiving any updates from FirebaseFirestore even when I log out and log in¹ with my user. I'm thinking maybe my authentication is set up wrong and that is why I'm asking here.

After logging out I do this in my classes that manage Firebase services (example):

    await _auth?.signOut();
    _store = null;
    _auth = null;

This means when I'm logging in again, I'm also calling FirebaseAuth.instance and FirebaseFirestore.instance too. Could this be cause for concern?

I assume not since it's a static field on a class and it probably returns a singleton. However I wanted to double check this before I start doing any changes.

Footnotes

1. When looking at my logs, I don't see any errors thrown by the library ↩