After 40+ flights - one or two tumbling "landings" - the Vision 2+ developed a habbit of shedding a lot of altitude very quickly.
The behavior was intermittent but seemed related to aggressive maneuvering and/or any kind of descent.
I tried zero power, forward pitching out - thinking it might be rotor wash (vortex-ring-state). I tried flipping to ATTI - maybe crazy GPS signals. I tried hard rolls, pitching backward, abything I could think of. Nothing seemed to break out of these falls.
At first I was losing a sudden 10'. Then, over the weekend it got much worse and I had 4 serious crashes. The first 3 left no visible damage - which is amazing. On the 4th impact the Vision 2+ camera separated from the gimbal.
Broken Vision2+ gimbal
After removing the gimbal. I recalibrated the IMU and went out expecting to watch the Phantom crash again. I was suprised to see the Phantom flying stabily and I was unable to reproduce the falls of the last few days.
I now suspect that the gimbal may have had a short. More testing to come.