Copter intermittently stops between WPs and just slowly climbs

I have had this problem intermittently for a while but can’t reliably reproduce it.
It will perform as expected most of the time, but now and then it will be between WPs, slow to a stop and slowly climb. Typically I can switch it to any other mode and back to Auto and it will continue with the mission. Or I can switch to RTL and it will return as expected, although once it went “dumb” (stopped and climbed) when in RTL.
Any help would be appreciated.


In this log, it happened somewhere between line number 80 and 100


So I flew the heck out for my Hexy a couple of days ago to try to get more data of the problem and it flew like a champ, not one issue with it stopping in a mission. But I am getting an occasional imu mismatch in the log analyzer. If you look at ATT_yaw over Desyaw, you’ll some deviation, but if not sure how much of a problem that is. It’s something I can not see or hear in flight, it seems rock solid. Now if you look at this log, you’ll see some large spikes in yaw, but again, it’s something I can not detect in flight and does not seem to be related to the problem…