Problems with assignments

Hello, I’m very entusiast about the app. Anyway i got the the following issue: I tried to createa custom layout, i assigned to every control a thing on ableton (a knob, a button…). When I change something on the effects, move some devices or something… or just using the custom layout for a time… the setting vanish and doesn’t work anymore until I reassign them. Why? I assigned them navigating inside the ios app. Thanls in advance!