Application does not return properly from extended sleep mode

Platform, device and operation system
Android 9, One Plus 3, Oxygen 9.0.6

What were you expecting to happen, and what actually happened
The game often does not return properly from extended sleep mode. Sometimes the screen is frozen; sometimes it is completely black.
Expect game to be able to recover, or kick to main screen.

How often does this happen? When did it begin happening?
Is this a once-off issue or has it been a consistent issue? Does it only happen in specific circumstances?
Since at least .0.38. when I started playing the game.

Steps to make it happen again
Please detail the steps taken to trigger this bug. The more detailed the breakdown, the easier it is for us to test in-house.
Have phone go in sleep mode for a prolonged period, say an hour.