When it would snap back, the location was correct, but the arrow was pointed in the wrong direction. As I continue to drive at, say, 35 MPH, as I would move 35 MPH one way, the arrow would move 35 MPH in another way (the way it was pointed, which is not the way I was actually pointed), so the location gets more and more off, until a short period of time goes by (which I estimated at 15 seconds or so), at which point it would snap back to the right location again, with arrow still pointed in the wrong direction. As noted, this lasted about 8 minutes over a course of about 4.5 miles last time it happened, and the prior time it was roughly the same.