Long Term, Unknown ADSB Malfunction

Just learned yesterday via FAA email that my ADSB install done in Aug 2018 has had Mode C and Baro Alt problems since new. After installation my system was test flown and adjusted by phone app until I received a good PAPR with no flags. I have assumed that my system has been operating faultlessly over the last year, not true. I'm corresponding with uAvionix and the avionics shop that did the work. I have spoken with an FAA ADSB team rep, he was informative and helpful. I learned that of the 100,000 ADSB systems installed about 7,000 are faulty. The FAA will "filter" me out of the ADSB system in 45 days unless I correct my ADSB faults.

Will the FAA notify the registered owners, if there is an issue with their ADS-B systems?

Absolutely. The certified letter reads more toward a deviation rather than notification.

The acro and formation guys found this out first. Years ago.

I was told that my problem was finally reported to me because it was persistent and had not been corrected. FAA ADSB records indicate that my ADSB has been faulty during the span of 100 flights. I have not looked at any PAPRs other than the one that accompanied my FAA letter.