Was that 12.5.3 version of FSD? They pushed the update to my car at the end of Oct. Didn't really get much of a chance to use it but the auto-pilot seems to be better with the update. I imagine you car has HW4? I think that will make a difference too. 
Now, I see that FSD 13.2 is out. That may further improve things but as you note with the speed limits coming into a town, the car is still hampered by only reacting when it sees something change. Every drive is a completely new adventure for the Tesla and it still has no capability to remember the speed limit sign that was there yesterday, and the day before, and the week before, and the month before that.