This is where it happens to me as well. Specifically one particular overpass and I have not experienced it anywhere else. I thought maybe it is because the are doing a huge I-4 expansion and have widened it so much that the GPS thinks its on the old exit ramp which is not the main lanes headed east? Its definitely startling. I start autopilot after this overpass when headed in that direction and don't use it until I am clear of Downtown and all of that construction.