This. I found the same issue driving to California and back over the holidays as well. Nav on Autopilot is helpful for suggestions and reminders but I'd never follow it blindly. Frankly I've found the NAV directions in general in the M3 to be only about 90% trustworthy. Frequently finding slower routes selected than google and in some cases just plain wrong (i.e. requesting two uturns rather than going straight through an intersection).
Don't get me wrong, its a nice perk, but it has a looong way to go for FSD as Darkenergy mentioned.