Guys has anyone experiences this?
After I switched the batteries off and back on, it went back to normal it's been ok since except once on a similar steep hill pull up earlier in my ride home I thought I felt similar issue kicking in but pulsed the brake on/off which seemed t reset things and it didn't, continue.
Smart thinking. No this has not happened to me yet, but, have you got the external controller?. Just the same I would check the wires going into the motor and see if the have lost their insulation and are not shorting out a little.
the brake switch can get stuck, If you have clamp brakes, the screws you use to adjust them to centre , I do both as tight as they go while still being able to manage centre. This will increase the spring tension and insure the brake levers are being pulled back into full position.
Check all your cable connections.
After reading your post more, I sense this controller has a dark future.