A beautiful sunset got me racing for the Mavic to get a better angle for a photograph.

GPS was good and I took off from my patio. Home point was updated.
    - on review of flight record there was a Strong Wireless warning - probably my home WiFi
Flew 275m towards my target at 105m altitude. No problems
While hovering the camera suddenly tilted giving me a horizon at 45 degrees.
I panicked and initiated return to home. While the camera gave me no help, the other flight data indicated that things were OK and visual contact confirmed things were normal. I tried to use the gimbal dial to regain camera control, without success.
Drone arrived overhead and began landing. At 35m there was a Gimbal Motor Overload warning.
Then at 1m the mavic stopped descending and began to spin around maintaining height and location. After 540 degress rotation, I pulled the left stick fully down and held it there.
The mavic stopped spinning and landed safely.

Is this another "out of control" return to home moment? If this had happened 100+ metres out, in the failing light, I would have stood little chance of a safe landing. I'm still a very new pilot just learning and building my confidence. Up to this point I had flown 23 take-off/landing cycles to a total flight distance of nearly 4 km without any problems. I am now just a little (lot) worried and feel like I'm back at day zero.

Compass calibration was done before first flight.
Firmware V01.03.0200
DJI Go4 on an iPad mini
Flight Record at HealthyDrones.com

Thanks guys.

What's the weather like? I've had 'limp gimbal' issues when it's cold. Sometimes the camera will flip farther than straight down on the bird's return and my real time video is upside down, looking backward. Once the bird is warmed up, everything is fine again. No flight issues for me. I'm using a Phantom 3 Pro, by the way.

The temperature was around 10°C and the Mavic had been running for 4+ minutes when the gimbal tilt happened. I should add that the tilt gave me a 45 degree horizon, it was not a downward tilt.