Well something is wrong with your system if you have electric brakes, then as soon as you loose power brakes should engage. Brakes should disengage when the deadman pedal is engaged, thus energizing the magnetic coil. MAKE SURE RELEASE BOLTS ARE NOT ON BRAKE ASSEMBLY!!! Removing the power in these machines, either by e-stop, or sudden lose of power, should halt the machine to a complete stop.

Edit: Have you checked your error log? Check battery leads on connector sometimes these become kinda loose causing this symptom.

I hate writing on this forum people never write back or they take forever to write back, it would be helpful if you write a question to check often for responses and to actually respond back if it helped!!!