I'm using Proton Pass and recently switched to Graphene. Autofill is enabled in Proton Pass and in the system settings it is correctly selected.
I remember that in the beginning I got at least some form of draw-over autofill but not in the smart bar of my keyboard. Now neither is working. I tried the integrated keyboard, Florisboard 3.x and 4.x beta as well as Gboard.
Not sure what's happening. Are there any other options I have to enable? Maybe something that allows multiple systems (keyboard, password manager, system) work together and this is some form of sandbox issue? I only use one profile for all apps currently. Proton Pass and Gboard are installed through sandboxed Google Play.