Since last or second last update of the game, it often happens, that after I unlock the screen of my Android phone (Oneplus 3T), I cannot just continue with the game like before.
Instead the screen is white, turns into black and the game obviously has to restart. Like a crash.
Fortunately my game doesn’t crash while playing, but nonetheless it could be an indication of a severe bug.
I have a Huawei P30 and this issue only appears, when my device is in power saving mode so the background activities of apps are limited and the RAM doesn’t save your session while being off screen.