To avoid the risk of screen burn-in, we recommend not letting any image sit for longer than an hour on your device. If you're letting it sit for hours without the display having time to go to sleep, it may have a negative impact on your display. This would be the case for any app with a static UI.
Unfortunately, there's nothing we can do on our end about this, but if you give your display more time to rest and not keep the screen on the game for an extremely long time you shouldn't have too much of this issue.
Note: You may also check with an authorized service provided for your particular device just to ensure that this isn't an issue with the display in general.