I had an odd experience today while driving in local traffic, both on El Camino Real in Mountain View - divided surface street, some traffic moving at the speed limit. I engaged AP (2017.28, AP2) following a pickup truck (with camper cover). Vehicle showed up on my screen, I followed normally under full AP. Truck stopped for a red light. My car slowed as normal, but got uncomforably close, then went into what I suppose is AEB. AP disconnected, loud warning, red warning on screen, car's warning flashers came on, hard braking. Either the car stopped itself or I did, at that point I was on the brakes (it all happened at around 5mph or less at the end of what is normally an in-traffic stop and go situation).
I shrugged it off as some sort of sensor confusion. But then 5 minutes later, on a smaller neighborhood street, I had the same thing happen with a car I was following under AP2 control stopped at a stop sign. Again, my car was seeing that car, and began the decel, but at the last minute entered the same weird state - alarm going, warning flashers started, AEB type brake event occuring.
Strange. I'll report back if it continues. For what its worth, I had following set to 1, and AEB set to early warning. Maybe they are overlapping?