Were you flying in Sport Mode? I had the same thing happen to my gimble when I was in sport and tried to go sideways really quickly. When I saw the gimble point at the leg I thought it was crashing for sure!
Which gimbal are you using? I thought that was unique to the H3-3D ... FF to 03:00 ...
I think ive fixed it by relocating my vtx and adding new rubber gromets (thicker ones) on my bird, took it out in strong wind yesterday and not a twitch.