The velocity sensitivity of the pads on the AR is a bit clunky. Try setting “track velocity to volume” to OFF for all tracks and see if the problem disappears.

The pads will loosen up in use tho. Initially I had probs with the pad velocities much more than now that the pads have been “burned in” somewhat. For decent velo sens tho, you need an external padcontroller IMHO. You can play the AR pads from any MIDI channel from the first 12 notes (ie. note numbers 0-11)