Platform, device version and operating system:
Android, 4GB RAM
What you were expecting to happen, and what actually happened:
I was expecting the game not to crash.
How often does this happen? When did it begin happening?
Started happening with patch 5.4. Happens frequently during/after claiming ad reward (which now usually opens the Play Store – also an unwanted behaviour), and also when changing back to another game that is running.
Increasing RAM to 6GB reduces how often it occurs, without actually eliminating all crashes.
Any game that requires that much RAM (or even 2GB) on a mobile device does not have proper memory management IMO.