This is an Android issue, please forward it to the Android team. Starting with the Sunken City patches, a bug that freezes the game just before the character selection shows up when starting a Battlegrounds game has been reintroduced. Only solution is force-shut down the app and restart it, with luck I’ll arrive for the 3rd turn. This bug was already in the Alterac patch, and was fixed later. It sucks losing 2 of every 3 games because of it.
And no, cleaning the cache doesn’t work, reinstalling the app doesn’t work, resetting my phone to defaults doesn’t work.