Just to add to the discussion about a ghost airplane. With a full in/out ADSB, the Transponder has a hardwire out that communicates with the ADSB unit. The transponder "talks-to" the ADSB unit and lets it know the transponder code being sent. The ADSB has another connecting wire that controls the transmit function of the transponder and can automatically suppress the transmit function, although I am not sure what the criteria for suppresstion is. The ADSB system will recognize that my transponer signal and my ADSB signal are from the same airplane. In some cases it may even suppress the transponder signal.
In a passive system which is for receiving mostly weather and ocassionally traffic, it does not have a transmit funtion nor does it talk-to the transponder. Your transponder is sending out a radar location oblivious to everything else. That information is sent over to the ADSB system which transmits all the aircraft locations for the area. It just blasts them all out. Thus your Ifly unit displays all the airplanes in the area which includes your airplane. So you are receiving all the traffic it just happens that the iFly unit is displaying you too as traffic.
If Adventure Pilot puts a filter in there I would suggest it be an option to turn the traffic filter on and off. Since in a rare circumstance it could be another aiplane close to you. The pilot can make their own judgements of what to display.
My 2 cents.
Dave