Had something like that happen to me in Corona, CA. In my case also, no warning, just WHAM! as I came down a steeply curved off ramp from the 91 Fwy. No flip back up, though. The cause in my case was pretty obvious, though. It was that nemesis of S. California bikers, the First Rain of the Season. In my case, the only injury was a dislocated shoulder, no great pain, but VERY noticeable when "officer friendly" (CHP) told me I couldn't leave the bike there. Duh!! At least he did most of the grunting to help pick it up.
I heard three calls on his squack box while we were discussing the situation so he didn't even take the time to check DL and registration, since there was no property damage and my injury didn't show - he had more serious problems to deal with.
The family Chiropractor is VERY good with dislocations, and made no nasty wise cracks. Got a new jacket with heavier shoulder padding, and replaced the scratched helmet visor.
I was rolling off the throttle when I lost it, but no brake. However, as I recall, both tires went out together, so deceleration had little to do with it. Speed less than 20 mph. Had I known better at the time, I'd have assumed glare ice traction and "paddled" the bike - which might have meant a cage would run me down, though.