I have a similar problem with an MF2/GTB/13.5. I unhooked the motor from the car and noticed that it always refuses to start from a specific position (when the flat spot on the rotor is facing towards the rear of the car) so I eliminated the gearbox as the problem. Novak thinks it's my ESC, so I ordered a new one... If my problem persists as yours has, I'm going to rip my hair out.
I don't know if this is helpful, but maybe one more way to look at it.