There’s a bug in something, i just don’t know which one may be. You may read something similar from this
In if you intend to use push notification, i recommend the @TimAi2 guides about web component as Authentication method whereby you wont use the Firebase.Authentication built in component. This will work, but changing of things/setup will be involved.
Also am working on something related to Firebase, but that can take a while to be released.
But for solution i may summon @Diego to investigate, whether the issue is with OneSignal/Firebase.Authentication