Heheh, Yah, Ms Garmin, my Arch Nemisis....
It just recently sent me into a private property, dirt roadd... I had the Avoid Dirt option on.
It'll hang you up.. but so with the others in different areas so just plan on it not being 100% all the time...
It typically, for me, will take me down the "Yellow Brick Road" out in the Boonies and then "Dump me" saying something like "I don't have the data for this.."...
I use a back up map when I can't get Google maps up on the tablet. Google has saved my bacon more than a few times where Ms Garmin just didn't know what I was talking about..
so, not surprising... but plan ahead.
One trip I learned from another post is use Google earth and ++++ on the roads in doubt. If you see the middle white line, it's paved.. if not? probably dirt...
Not much help, but you're not alone...
Good luck..