Hex 550. Pulled it back out after not flying for a couple of years.
Just installed 3.6.9 Flew this frame, ESCs, and motors a few years ago. No problem with default settings. Different FC in different position with vibration damper (didn’t have before).
With props off, motor speed increases steadily (from sound and servo outputs viewed in mission planner) before and after.
First flight, gradually throttle up, suddenly throttle either off or (apparently) full on. (Miraculous landing with no damage).
I think the log file also shows the testing after with props off, gradually increasing throttle input.
Pretty sure I used the ESC calibration on ESC’s that do not support it. (Hobbyking Red brick 50a opto). These worked great before I made the changes. Great performance, stable flight. (Reliability not so much).
I reset the programming in them and will try again. Long term I will replace them. They are greatly oversized for my hex.
I’m having the same sort of issue, throttle has detent clicks, one click and it changes from a slow fall to a fast rise. I was going to try the throttle slider first to lower the sensitivity. My hexa also ping pongs up and down in alt-hold and position hold, but It was very windy too. That was my second flight so it’s not tuned at all.