C note get stuck during or after roAt play

[twerq]

C (Do) note stuck when playing RoAt. It is like permanently holding C note on.

I've checked the ribbon and it's okay. I even connected midi keyboard and didn't touch the ribbon keys. After some play with RoAt I notice strange keys behavior: at some point RoAt OSCs won't activate/deactivate by slide as expected. Then I turn to another nts-1 OSC and hear permanent C. Switching envelope type won't help. Even in ar env mode I can hear that C for a second or less in case of release open or not. Only power off/on helps to get rid of stuck C.