I discovered problems with mine because sometimes the HW ESC triggers green flashing light and the car goes slow (goes out of turbo mode) even thou the battery is newly charged. It never happened before, and then started to happen recently.
I took the motor apart and swap another new motor's sensor cover on, and no more problem.
I guess it is harder to detect when running in MOD mode (non-turbo), as I think if the sensor is not working, the esc will just operate in non-sensor mode which is harder to detect. Probably then the linear-proportion will not be as good. And maybe check out if any lights are flashing on the ESC.