I got my 3 for over a month now and the car had been great until Autopilot behaved strangely today as it was trying to change lane. I was traveling on the 405N (~6:30 PM) at approximately 75 mph with AP enabled. After checking for clearance on the right lane, I signaled for AP to change lane. As expected the car moved over, but for no apparent reason AP applied the brakes pretty hard as though it was trying to stop the car. There was no car in the front. As for the rear, the distance of the car behind was pretty far luckily. We were in middle lane of the freeway. Noticing the car had slowed down significantly, I quickly stepped on the accelerator to avoid rear ended and took over the steering wheel which jolted the car slightly as it disabled AP. It almost gave me and my wife a heart attack. I didn’t rengage AP for the remainder of the trip. Has anyone experience this while allowing AP to change lane? I’m on 18.13 firmware.