It’s appropriate that the first video is called “gimbal”, because that’s exactly what it is.
Watch the angle readout at the top of the video. The rotation of the object happens exactly around the time that the angle passes 0°. Why is this?
Have you ever watched a PTZ security camera rotate up and over the vertical axis and down the other side? It will tilt up until it nears the vertical axis, at which point it will rotate around that axis ... Read even more