This problem can happen in any time (When I start my mpc or after 5 minutes or 30 minutes and so on during working process and it happens only once a 12 hours using process)
This issue can disappear in 15 seconds or 1 minute or - after rebooting
I donn use a any midi controllers, it usually happens during normal playback.
This problem is occasional not constantly happening, sometimes it doesn't happen at all and then in approx. 3 days it starts again.
This issue doesn't bother me too much but really wanna fix it, maybe cleaning internal circuit will help.
Thanx in advance!