I just have to wonder about compass calibrations when I see these telemetry videos. I have a very VERY similar thing happen just the other day. Trying to get more stick-time, I took the copter out to the front yard (I live in a cul-de-sac) as I have before to get a little practice in. I took off, flew 20 minutes and went in to charge the battery. Came out an hour or so later with a freshly charged battery and attempted it again....
...this time, I took off and let it hover at around 3 feet for approx. 30 seconds. During this time it had this sort of "right-slip-twitch" to it. Not a gradual movement to the right, but a twitch! A very quick, almost violent half-second jump to the right, and then re-level. it stopped so at 52 seconds into this flight I gave it about 50% forward stick, still at around 5 feet altitude, for a distance of about 20 feet.
Then as I brought it to a halt, to spin 180 degrees and return back, the Phantom 3 Pro started drifting right and climbing. It climbed from about 4 or 5 feet alt to about 20 feet and drifted right about another 20 feet while I applied more and more left stick to bring it to a halt.
Thank goodness for my previous R/C airplane experience!!
...I was able to stop the right drift with almost full left stick, and I applied down throttle to attempt to bring it closer to me.
I was able to back-up the drone, bring it back down to about 3 feet in altitude, and I centered the sticks.....which to my chagrin made it drift right....right into the neighbor's tree!
Minimal damage ( actually NO damage, just mud and scuffed props)...but it utterly destroyed my confidence, and trust in the copter!!
...so I'm taking this time to order some prop guards, peruse some fly-away videos, and collect other user experiences ( hence, why I'm here- just to rebuild some confidence...
...not confidence in my ability, but confidence in that this thing isn't going to have a mind of it's own!
Did you drop into Atti mode? I would get compass and GPS errors right after lift off from a concrete driveway. Now I only launch off the lawn. And have not had the same error.
But if you had been flying for a while with no errors it had to be something else.