Random MIDI OUT garbage

Musescore 4..2.1.2nnnn

Using the score as a MIDI controller to reproduce the score on my Korg Triton has not worked in months of trying although the keyboard is recognized by the ubantu OS and the midi interface. There seems to be no clock to sync to. Keyboard MIDI IN in editing mode works. What's worse is even with BOTH MIDI In and OUT interfaces disabled in Preferences, the program will randomly send a flurry of note and command signals to the keyboard in a jumble of notes and noise when the score is placed in Play mode. The MIDI interface I'm using (Nexus Plus and Uphoria) both indicate this data coming from Muse. Nexus is in a mode where the only input it can get is from Muse and Muse is set so its only input comes from the Korg. With all the Korg's MIDI options disabled (except notes) the notes still come through in a chaotic jumble and do not stop until I stop play. The only work-around is to restart the program. What causes this is hard to predict but possibly has something to do with toggling the MIDI options off/on. My understanding is with BOTH MIDI options set to off there should be NO MIDI coming out of Muse at all at any time.