I’ve followed the instructions in the manual precisely. After mounting the camera to the stabilizer and pressing the power button, I see the stabilizer try to tilt the camera and then I hear a quick buzz and then three beeps, and then the motors all shut off. Occasionally it will stabilize for a few minutes or so, and then after some very gentle repositioning and scanning without going anywhere near the motor limits, the buzz and three beeps occurs. What’s going on?
first off, what do you mean by instructions? 
But yes mine does this as well. Mostly random but seems to happen when panning to the left more so. 3 beeps and what sounds like a gear seizure!
double clicking the mode button can sometimes snap it out of it but it will come back
I could do all sorry of movements including tilting , upside down fast and slow and no issues or shutting down of the motors unless I touch the scanner and prevent it from moving then the motors shut down .
I guess your stabilizer has a very sensitive sensors .
I will tag in @Revopoint3D-Gena to check in on this issue as it is definitely not normal behavior you are experiencing.