Ok… (facepalm) the problem was twisted start knob to value 2, so this was a reason why OT was playing stem from incoherent position. It is impossible to see that kind of value change if you look at it in a “knob mode”. I could notice that change only when I switched to chromatic setting, because it shows numeric values.
Well… here it is. What can I learn from this. OT is awesome, but also very complex beast. Just one accidental knob move and you are into bad place especially when your *ss is on fire before performance.
I hope it will never happen to you guys, thanks, take care!