Another thing I've noticed specific to FSD routing (at least, I assume it's FSD-specific - it didn't do this before I got into the beta) is that it will sometimes make very strange routing choices in order to make the drive easier for FSD to handle. One example, I was leaving my local Subway the other day and started navigation that required me to get on the highway about a half a mile down the road. To do this, however, you had to turn left out of the parking lot, across double-lane traffic going in both directions - a crappy driving situation for sure, but it's clearly the fastest and most efficient path forward. However, FSD instead wanted me to turn right out of the lot and turn around far down the road instead - adding several minutes of time to get to the same spot, but in a way that was infinitely easier to accomplish.
I just made the difficult turn myself, at which point the navigation rerouted and I engaged FSD, so it wasn't a big deal...just interesting. It definitely threw me off at first though - I couldn't figure out where on Earth it was trying to send me! I have to assume that FSD didn't want to attempt making that difficult left turn.