Why is my app still considering the user as logged in even after deleting their account?

Question

I deleted all my collections and also went to the authentication tab in Firebase and deleted all users. I then went to Android studio and hit the stop button, then hit the play button again. Upon start, Logcat says that the user is still logged in:

2020-12-25 17:20:05.410 29800-29800/com.example.mumble2 E/ActivityGroups: 1
2020-12-25 17:20:05.444 29800-29800/com.example.mumble2 E/ActivityGroups: User is not null
2020-12-25 17:20:05.444 29800-29800/com.example.mumble2 E/ActivityGroups: User: com.google.firebase.auth.internal.blah

And the app stays on the Groups activity too (the app's launcher acitivty), instead of going to the login/signup activity. What am I doing wrong? Why isn't the app recognizing that the user's account was deleted?

class ActivityGroups : AppCompatActivity() {

    private val firebaseAuth = FirebaseAuth.getInstance()
    private val authStateListener = FirebaseAuth.AuthStateListener { firebaseAuth ->
        val firebaseUser = firebaseAuth.currentUser
        if (firebaseUser != null) {
            Log.e(tag, "User is not null")
            Log.e(tag, "User: $firebaseUser")
            loadGroups()
        } else {
            Log.e(tag, "User is null")
            Log.e(tag, "User: $firebaseUser")
            val intent = Intent(this, ActivityLoginSignup::class.java)
            startActivity(intent)
            finish()
        }
    }

    override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            setContentView(R.layout.activity_groups)
            Log.e(tag,"1")
            ...irrelevant buttons...
    }

}