Hi nickrose,

Thanks a lot for your answer.

There was a “CC32” slot that I lowered to zero on the HX, is that what you meant?

One possible cause for volume drop issues is that some products send out a MIDI bank select on CC32 which can be used for H9 Swell functions (ISW,OSW). Check these in the system menu and move them to another CC or disable and see if that makes a difference.