It occurs to me that we added MIDI START and STOP to the V5 Looper. The Looper will always respond to these commands (details as to how are in the Looper manual in the info tab in H9 Control). It's possible that Ableton is sending START and STOP when you play your loops (a lot of DAWs do this by default) and there might be contention b/t these and your CC values that you manually programmed to do the same. Maybe try a simple setup without sending any of your CC's for START, REC, and STOP and see if the Looper responds. Alternatively there may be a setting in Ableton that allows you to turn these START and STOP commands on or off?