Like Dan-Nickie wrote something along your route is triggering the system to warn you. If the roadway is raised and there are other roads crossing beneath it, several lanes split off, a bridge, overpass or name/designation changes the system tries to keep you heading in the right direction.
My AT&T navigation app actually shows which lane(s) I should be in. Maybe your lane choice is causing the system concern for example it expects you to be in the number 1 or 2 lane and you are in the number 4 lane.
