Cannot update automation lane to zero level

Hi everyone

I’m trying to figure out why when I update my Expression and modulation automation tracks with my XY pad (TouchOSC on iPad) I can never get the levels down to zero.
Or to be more precise, I go all the way down to zero and immediately the level resets to 1 or 2 on the automation track, even though the XY pad’s sliders are at zero.
I didn’t have this problem before, but I don’t know what I’ve changed, apart from using QuickControls and midi remote.
However, my levels are set from 0 to 127.
The automation merge mode is set to Replace 1 or 2.

Any help would be appreciated!