I can get stuck notes on playback, record, loop, non-loop. I really can't pinpoint where or when it will happen. The only way for me to reset is to make the plugin inactive then active. I'm working mostly on an iMac with Pro Tools 9 but, as I said, in the past couple of weeks have tried it in various 'studio' situations - Mac Pro, Macbook Pro etc.
It is frustrating, but the only good thing to come out of it is... It crashed in a spectacular fashion in sequence mode and started throwing out the weirdest Radiophonic Workshop, music concrete-y, early electronic stuff out.
Nearly blew out the monitors, but I managed to pull the channel down just in time.
Of course, I haven't been able to replicate that, so good job i hit record when it happened.