In our Firebase demo when a user removes an application - a private key is deleted, as well as all information about the application - Android works this way.
The user sends a message to another user and when the receiver reads the message - it is written locally in the database and removed from the Firebase’s database.
That is why, when you start using a new device, you are prompted to generate a new key pair (because the card already exists for this identity).
You won’t be able to read the history, because the private key is not transmitted + the message after the first reading is deleted. So this is the expected behavior.
For more details, you can read the article here: https://github.com/VirgilSecurity/demo-firebase-android