Ok I had this Issue B4. I have a iPad 10.5 pro. I believe it was either Another iPad that had that issue or it was a previous issue w a different 10.5 Either way it is most likely not the game Its the device. I believe. Because on another device I also had an issue with a darkish water mark like square underneath in the background n the device was new.
so u can try re-downloading the game but make sure u are of course signed in to a account so u don't loose your stuff 0r if that doesn't work try resetting ur settings or giving the device a hard reset & if tht doesn't work call apple or bring to a apple store n tell them its a defective iPad.
obviously save everything first to the iCloud so u don't loose anything. But yeah Dealt with exact same issue. so first try resetting stuff.
if it is device then exchange it. apple will do that if theres a defect at the apple store. they want u to be happy & going to their store they don't want a scene so if it like my device b4 had a issue that was their fault they will most likely exchange a new one out for you.
Because Im on a iPad 10.5 @nd its detail is defiantly great. hope u get the issue fixed.
Im always glad to shed light on stuff n help out fellow tapperinos.
Best wishes.