The stuck notes were an accident, and the drone notes aren't controllable or predictable.
I created a basic program, and created a split. I wanted the left hand bass to be thicker, so I put it in unison. I was messing with unison detune and number of voices when I got stuck notes. Having already spent 20 minutes fine tuning the upper layer, I didn't want to lose my work so I opted to save at that point. I figured I could scroll to another program and back to stop the stuck notes. Nope, still there. So I rebooted. Still there.
Worse yet, if I took it out of split mode, I got additional very high sounding stuck notes.
So this is very much a bug. And is also why I was asking if there was an All Notes Off command.
Come to think of it, I was also dabbling with the VCA Env amount and levels, trying to balance the 2 layers volume wise.