Hi dtmcinto,
The problem you are experiencing is because you are trying to use a TRS expression pedal in [BOTH] or Expression Pedal + Aux mode. This mode requires a TS expression pedal. Check out this video, which explains it clearly. It works the same with H9. It also explains how to make the custom cable you would need to make things work with your Dunlop pedals. Go to 9:50: https://m.youtube.com/watch?v=lfi0sbn5c5Y
