The other evening we were driving on a clearly lane striped highway, the display was showing the lanes with no problem, light traffic, good lighting. I changed lanes to the right with the signal stalk, which the car started to execute, and after it got about half way done, I let go of the stalk and the car continued to go into the new lane as normal. However, it kept going into the next lane to the right. There wasn't anyone there, so we let it go to see what would happen. It got about half way into the next lane, with the lane marker about at the middle of the car. The display screen clearly showed all this as well, with the car icon moving across the lane marker about half way, then correcting back, so the car at some level knew what was happening. There was another car about 2 lengths ahead in the lane the Tesla erroneously tried to go into, shown in gray on the display, so the car sensed it, but wasn't following it. The lane markers on the display were always clear and blue. This isn't the first time our Tesla has overshot on line changes with another car in the next lane over. I'm wondering if the CPU is overloaded and/or there's a software bug. It's trying to characterize the car it senses ahead and in the next lane and at the same time trying to complete the lane change. Not knowing anything about AP's internals but having done some real time programming, I wonder if they are using cooperative multitasking, but have a CPU hog in the code that's not doing enough yields. The thread trying to figure out what the deal is with this new target in front and to the right isn't letting the other thread, which is trying to complete the lane change, run enough. The chip has lots of CPU's, but who knows how the code is organized.