I have found with unexplained glitches in a generic sensored/sensorless controller is to disconnect the physically ignition wires, unplug the battery and come back to re-attach. Thinking about it now, its probably best to wait until there is enough time has past for the capacitors to discharge naturally. I have no proof it'd help and I dont know how long I left mine unattached before reattaching and the mysterious failure has stopped. It has helped me with unexplained happenings with the controller, that happened long agothat I forget what it was, but it has helped me several times after I tried all the common sense approaches.
If the issue cant be solved, then maybe a unplug every wire on the controller, let sit over-night and try again to fix the issue.
I doubt that its your issue with the unknown motor, unknown controller with no care to expand with more detail I then speak in general terms for others, maybe they remember my post, maybe unplugging wires works maybe it doesnt but what else you got?
Other things to look at maybe the bearings like loose bearings getting jammed up, cheap bearings are like that.
Might always be stiff, maybe its dirty in there, or more that its a bit crusty as they say. Lots of flex, what the quality of the motor, we need an overview, details of the problem, details is the key to answering questions with no details.