I had this happen twice on my P4. I didn't notice it on the first time because I couldn't see the camera well (using my phone), and the video was ruined (sigh). Second time, with FPV goggles, I forgot to take the gimbal lock, then when I took it off, I had a "crooked" picture again. Next, it seemed like the the camera always faced straight down. A shutdown/restart of the aircraft fixed the gimbal problem, and it hasn't returned.
Believe these were all mostly "pilot inexperience" on my part.
Now, I always check the gimbal before I fly (make sure it's working well before I move away). Now, I've gotten much better and the video shows this.
If you find this error to be repeating, you might need service.