When selecting a planeswalker the the screen often overlaps the main selection screen. This often happens when tapping quickly on the planeswalker select screen and then pressing back, without the full animations playing. It happens with the in game back button and possibly with my android back button as well. The overlap dissapears after going fully into a battle, but doesn't allow you to check any other screens.
It sounds like you may need some more troubleshooting advice, please submit at: https://magicspellslingers-support.wizards.com/hc/en-us/requests/new and select 'Technical Troubleshooting'.