Hello. I got Samsung Galaxy S9 (Android 9.0) with on screen buttons. These buttons are always visible except fullscreen apps like video players, games or gallery in presentation mode. Lightroom Mobile probably presents itself like fullscreen app in the edit mode so the Lightroom tools and Android main buttons are overlapping. Android buttons hides after a while but when you want to bring them up again (to go back for example), you have to swipe up from the bottom edge of the screen and you are interacting with Lightroom edit tools at the same time so you have to be really careful to avoid accidental editing. Buttons shows correctly in other parts of the app like main screen and browsing albums though.