Are you using the game most recent version?
If no you should update it, and one more thing use a game booster it will not just boost the performance of the game but it can also improve the graphics for this game the only thing I can think of it was a bug or a glitch.
If this is an in-game problem then the issue is not your device fault but rather the game itself I suggest you contact the game developers by using there contact and report it to them.
Plus they might give you more details about this problem and they may advice you on how to fix it good day lad.