So how to begin

I bought my P4 last year and had initially some major issues with using my Samsung S7. After the update that was pushed this january it is now working without a single error.

Since I now can use the drone as I want to I have started testing out different ways of using it, like flying in sports mode.
Living in Norway next to a large fjord I always fly over water, there really isnt much else I can do, so I am always very wary of what could happen when flying it as there is always water below.

Sport mode is working great, flying almost steadily in 20 m/s makes for very different flying than the usual 6-8 m/s in standard mode. However I am having some issues with the gimbal and camera that manifested itself yesterday in a scary way.

A few times before the camera have tilted itself so it looks like the drone is not horisontal but almost on its way to crash (30-50% angle) but yesterday when I was 1.6ish km away the same thing happened again, but this time I saw even more of the rotors and the camera got locked in a position where it was filming upwards to the rotors and I had no control over it. The position of the camera was at the max as seen on the Go4 app, I had absolutely no control over it, luckily it was at least horisontaly aligned and not filming on a angle but it was really hard flying it back to me as the only thing I could view in the camera was the rotors, the sky and mountain tops. When I got it back home I restarted it and the gimbal and camera worked as normal again

This cannot be normal but it keeps happening to me and only in sports mode. the camera starts moving by itself and it is really scary when it looks like your drone is about to crash because the camera is moving so much in very unnatural ways. It has only happened with me in sports mode and at around 20 m/s. I can see in the flight data log, when I replay it, that the camera starts acting up.

Is there anything I can do to prevent this from happening? I dont see any good reason for it and havent read about anyone having the same problem when lurking the forums here.

Thanks in advance

The gimbal will play up in sports mode if you fly the aircraft fast and perform sharp up and down turns etc,also in higher winds , the gimbal hits its end points several times in different directions, and looses its centering, then causing it to center in a different position, in your case 'up'
Its happened to me once, but I was really pushing the aircraft's capabilities, then the gimbal went all over the place, so I think it was trying to work way out of its perimeters and got confused to were center was, causing it to recenter in another position.
I have never had a problem with the gimbal flying how it should be flown.   

I had this same problem in P mode, flying straight and level. The gimbal suddenly swung up and to one side and stayed there. I had to bring the P4 back by RTH.   When I landed and turned off the battery and then turned it back on, the gimbal straightened back out and it has never done this again.  I do have an occasional twitch from the gimbal when it is pointed straight down, but it has not locked up again.