Since the last major update, Hearthstone on my Samsung Note 9 will go back to the main menu just as it’s about to start a new match. It will spin and look for an opponent, but just as it’s about to load the mulligan screen, it will go back to the main menu. I have to close all apps and launch it again to reconnect to the game that started. It seems like it might only for Ranked matches as casual matches load fine.
I can also confirm this. This happens on my Galaxy S9 when starting a new wild ranked mode game, I am taken back to the main menu. If I start the ranked game again it will put me back in to the game.
Also, not sure if this is related however, if I copy an online deck from my Galaxy S9 I am taken to the Main Menu and not able to paste the deck in to Hearthstone.
To clarify, it looks like the ultimate issue is when Hearthstone thinks that I’ve brought up a different program. I run an addon called Arcane Tracker to track my deck and the ranked matches load fine if that app is closed. However, if I should switch between apps while in the middle of a game, it brings me back to the main menu and I have to close out and start it up again to reconnect to the game.