I've done 25+ full battery flights with ALMOST no issues.
I did have one flight, might have been the 20th flight, where it asked me to do a compass calibration before I took off. I was out on my boat at the time trying to get a sunset picture over a lake so I had to do the compass dance on the back engine cover. I got the light signals for a successful calibration but I think it was my fault for doing it on an unstable surface over a V8 engine with a subwoofer next to it. That did cross my mind while I was doing the dance but I just HAD to get that sunset pic. Bad idea. I took off to about 30ft above the water and the GPS hold was doing huge slow circles that got faster and bigger with each rotation. Then after about 20 seconds of flight and a few jitters, it took off full speed roll to the right. I countered it by doing full left roll. It was acting as if I was fighting a completely different signal that was telling it to go right. Next, it started to fly straight back, which I then countered by pushing the control stick forward. I was sure I was about to dunk my Phantom in the lake. After about 20 seconds of receiving mixed outside directional signals, me fighting against them, my Phantom Vision literally swarming over my boat, and my heart racing, I decided to take it up in altitude. When I got it up to about 150ft, it finally calmed down but was still trying to go in different directions with less power. It mostly wanted to roll right. I managed to get it down over my boat and kind of did a hard landing onto the floor of my boat just so I could save it from going into the lake. I landed straight on the gear but one of the props hit the inside wall of the boat and broke it. I went back to land, put on a new prop, and did a proper compass calibration in my backyard far away from anything electrical. After that, it took off and acted as if nothing had happened. Held rock steady with GPS hold just like it always had.
Moral of the story, do NOT do the compass dance anywhere other than a flat area away from everything. I found out the hard way how serious and sacred the dance is.
And no, I did not get the epic sunset shot.