That's weird. Google maps seems to prefer to direct me on a kilometres long detour than to take a simple u-turn into an empty driveway. They do seem to have rules about u-turns, they just don't make sense.
As I got further and further away the "turn left here" and "turn right here" directions got more and more frequent, until eventually he just started repeating "turn around where possible" until I was able to find somewhere reasonable to stop and turn it off.