So yesterday I tried ActiveTrack for the first time with my P4, and noticed that while it did a good job of following me it gradually lost altitude as it did so. Around the same time I noticed that when stopping from forward flight, the Phantom would dip down a bit before returning to it's original height (slightly concerning but nothing too serious). Today I saw there was a new firmware update so I installed it, did a cold IMU cal, etc, and took it for a spin. Everything seemed fine at first, but as I was on my second battery and flying relatively low, I began to notice again that it would suddenly drop attitude when stopping from flying forwards, and gain altitude when stopping from flying in reverse. (Sideways flight seemed for the most part unaffected.) What's more is, as I continued to fly, the effect became more and more pronounced whereby it began to lose altitude DURING forward flight as well as gain altitude during reverse flight (fairly quickly too) without me ever touching the left stick. The degree to which it drops/ascends seems to be proportional to the the Phantom's speed. As an example of what I was experiencing this evening (all of this without ever touching the left stick): If I fly in reverse starting at an altitude of 10' I may end 30' up after flying backwards 40'. As soon as I let go of the right stick, the Phantom will begin to drop (sometimes for several meters, with a risk of crashing into the ground unless I apply the throttle) before regaining a stable hover at whatever altitude it happens to be at. What the heck is going on here? Anybody else experience this? It flew fine when I first got it less then a week ago. Edit: forgot to add that the DJI GO App does not seem to show these changes in altitude I've described.