MIDI playback on Note Entry

I’m baffled by an issue that I cannot find documentation on:

Suddenly I have an “extra” piano sound from my MIDI controller (which has no sound) on note input (added to the instrument that it is supposed to be, so e.g. sax now has sax+piano playback on input). How and where do I turn this off? The manual is no help…

I may very well have hit a trigger key to set this up, but I cannot find what it is. Playback outside of the controller is fine. I have looked at all settings, restarted the application, restarted the computer, dis/reconnected the controller, tried to reset the MIDI set up, all to no avail… and I am no novice at this either…

Many thanks,

Sebastian

UPDATE—this issue disappeared as mysteriously as it came on by the third time I pulled all the wires and restarted my entire system and reconnected. This time I also disconnected all power, and waited 15 minutes before restarting. Haywire volts to blame?

Are you on Win or Mac? And if it is a pure MIDI controller that you have, without a sound module, then the question is, where does the piano sound actually come from.
If on Win, it could be the built-in GM Wavetable synthesizer. Also have a look at Dorico’s mixer window (F3) and see if you can identify an audio channel, where that piano sound gets routed through.
If it happens again to you, then in that moment please do from Dorico’s menu Help > Create Diagnostics Report and post the corresponding zip file here. Thanks