Hi, this sounds like a firmware issue but I may be wrong, even though I’m on the latest firmware…
My Super Gemini has recently come back from repair - I think a motherboard replacement. Everything seems fine when listening directly with headphones. The transpose doesn’t seem to work on the upper layer but that might be a user error…
However, over midi when listening via my daw it’s a different story - the master volume doesn’t work, notes stick/hang, and a bunch of other issues.
Has anyone had similar issues?
Edit: binaural doesn’t seem work either 
Sounds like a absolute nightmare, think if it was one of my ‘old’ synths I would open it up and check that everything is seated OK as it sounds like a ribbon cable (or two ) has become loose or maybe chips not seated fully in their socket. However the Gemini is mega expensive current flagship so I think I would contact UDO Tec support to see what they suggest. NOTE: UDO do NOT read this forum much at all , if ever.
Thanks Andrew, I’ve given dropped them an email as would prefer not to open up if possible. Ideally don’t want to send back again as not cheap with the courier etc!