Heey Roughael,
I’ve tried to reproduce your issue but with my personal setup which is slightly different (specifications down below). Everything worked fine and I couldn’t reproduce your issue, which makes me think that the problem is not with the Duo but with either Cubase or the ur22.
What you could try though is updating to the latest Release Candidate and check if that resolves your issue. Please let me know if this helps otherwise I can do some more investigating.
Also, is your amsynth plugin updated to the latest version?
My setup:
Device: Mod Duo
Firmware: 1.11.0.2496-RC2
OS: Windows 10
DAW: Ableton Live 10 Suite
Audio interface: Komplete audio 6 MKII