This bug is known for:
Samsung Galaxy Note8
Samsung Galaxy S8+
It may affect other Android devices
When going into "setting" on the POWERUP FPV app, you cannot access the back button of the phone. When swiping the sidebar into place, the back button does not appear.
Temporarily: After changing the required settings > kill the app > open the app.
Temporarily: Use another phone.
The POWERUP FPV app will be updated shortly and this bug will be fixed, check for updates.