It could be a GA aircraft that recently had a transponder that was repaired or replaced. The Flight ID (N Number for GA aircraft purposes) may have been entered and “saved” incorrectly to the replacement transponder, using your aircraft’s N number.
Another possibility is that your N Number is being entered incorrectly as the Flight ID in an aircraft that has a transponder that allows the Flight ID to be changed. This is mainly true for airliners and fractional operators that use callsigns, so that the Flight ID can be changed in the transponder to match as the radio callsign changes for each flight segment. In years past, there were various flights that would broadcast all sorts of wacky words and phrases as part of the Flight ID data block.
If this issue continues to occur, then you’d need to communicate with someone who has an ADS-B receiver that has decoded an actual transmission from this unknown aircraft. Besides the Flight ID (using your N Number in this case), there will also be the ICAO Mode S hexadecimal code. This Mode S hex code can be entered into an online database to figure out the correct N Number and registered owner of the aircraft that is transmitting the incorrect Flight ID resulting in corrupted data shown by FlightAware.