I frequently travel between CT and MD via general aviation, and there has consistently been missing data between Potomoc and New York TRACONs. Allentown and Harrisburg TRACON data doesn’t show up, which means about 70% of the flight is missing. I have previously seen this data appear, though I can’t recall how long ago it was since it last worked (at least a couple years).
A lot of times if your flight is totally within TRACON airspace the data does not make it to the big ATC computer in the sky which is what is sent out to users like Flight Aware. VFR flights have the same hit and miss record. Kind of like sports, Arizona beats Cal Poly by 11 back at the beginning of the season then blows out highly ranked Gonzaga by a bazillion tonight, you just never know.