Why do I see a “ghost” aircraft mirroring me in ForeFlight Mobile while I am using my Stratus portable ADS-B receiver?

If your aircraft is not equipped with an ADS-B Out system, ATC can rebroadcast your Mode-C target to nearby ADS-B Out equipped aircraft. If you receive that transmission, it can cause your own aircraft to be displayed as a nearby target, usually slightly behind your actual position and +/- 100 to 200 feet in altitude. The only way to remove the “ghost” target is to turn off the Traffic layer in ForeFlight Mobile. If you have ADS-B Out installed on your aircraft, ensure that you have the “Ownship ADS-B” option selected in ForeFlight Mobile.