Just received 2018.21.9 yesterday evening, took it out for a spin: I did see the extra vehicles in adjacent lanes on the dash display, and I did experience the slowdown on an exit from the same lane off-camera. Generally, this firmware build performed as well as prior builds. HOWEVER, the on-ramp offset maneuver is still there, and in one case I nearly collided with a car in an on-ramp lane as I passed an on-ramp lane. I observed the offset on both right- and left-side on-ramps, and a whole-vehicle slide to the right at the on-ramp where I've observed this happen before. Tesla needs to put more weight in the AP calculations on the white lane markers on the left (or right) when passing an on-ramp to help keep the vehicle on the road. Tesla also needs to start using the ultrasonic proximity sensor data in AP to avoid side collisions ALSO, note the end of the video, where I demonstrate the "feature" that AP can be activated on the wrong side of a two-lane road. Tesla needs to fix this ASAP. Just think of the bad press if a drunk driver in a Tesla gets on the wrong side of a two-lane road, activates AP and gets into a head-on collision. Tesla should also throw up alarms/warnings when someone drives across the center line of a two-lane road even if AP is off.