No throttle or PAS sometimes after coming to a stop. NO error message and lights and display or still on. Just no throttle-PAS. So Far if I turn the power to the bike off with the on off button power is usually restored after one try. I spoke to a RADCITY tech at a dealer in California and he had the same problem but his solution was to cycle the PAS down to 0 and then cycle up and the power would return. I'll try that if when it happens again but this is very annoying and potentially very dangerous depending on location when this occurs. I asked RC tech if the brakes cutting off the motor could be a culprit he said no because he had those cables disconnected on his bike. I asked if there was a wiring diagram showing where and what each connector was tied to and he said no, RC would not let them have one. That amazed me and I thought it was illegal now for manufactures to do that. Anyway if you've had this problem and figured out a hack I would greatly appreciate it if you share.
A couple of years ago it would happen to my Radrunner. On mostly pedal power, I'd run an errand to a place about half a mile away after the bike had sat in the garage overnight. Shortly after starting back, I might find that momentarily I had no throttle or PAS. Once I hopped off and pushed the bike across an intersection because without the motor, accelerating a 1-speed bike on an upgrade would have been too slow for safety.
I never saw any moisture in the controller, but opening the case and spending a few minutes with a hair dryer would fix it for several weeks.
per a suggestion from a bike shop near me that services Radcity I disconnected the brake cables (not the hydraulics) and so far no stalling. will report back if anything changes.