Multiplayer Hide item bar, item in hand glitch

My friend and I were playing minecraft pe as usual. And suddenly they had issues where they can't see their item bar and held items. Also the controls disappeared for them too. We tried changing the HUD and reset all the setting, but it keeps happening in my world. Can someone please fix this. Or is there anyway to stop this :<? They can only access settings in the home page as all the buttons on the tablet goes invisible.