Each time I switch on the machine, playing any keys or selecting a Synth sound, a sustained note plays and won’t switch off until I hit the Drum button to reset it. Any clue why this is happening?
Video
Maybe push sequencer and disable sequencer?
That doesn’t do it either. Each time I switch on the machine, and press ANY keys that sustained note will play on and on. Help!!! 
Perhaps one of your effects is self-oscillating? Iter sometimes self-oscillates/ feeds back, so maybe it has to do with whatever synth preset you are using?
That’s what I thought, but after a factory reset and firmware update again, the issue persists. I have contacted TE to see what’s wrong with it.