I got something similar yesterday, freaked me out. The gimbal would start up in the right position, but would slowly get into a crooked position and then start making abnormal motor noises. What solved it for me was a recalibration of the IMU.
I went back to the manual to see if I had done something wrong, and noted that the gimbal should NOT be connected/disconnected when the Inspire is ON, which I think I did at some point.