Can't say much without a link to the actual place. Sorry, I don't recognize it offhand. I used 2020 data, so maybe that's the difference? What data does it show in pinesXT? All I can say is that, if it's on the map then it was part of the NJGIN shapefile that I downloaded. Post a link and I can tell you more.
I don't think it's unusual for lots to be combined... is it? Happened to my own property before I bought it. On the old tax maps, it shows as two 5-acre parcels but they were joined into a single new parcel later. As I understand, this was because a law was passed saying 10 acres was the minimum buildable lot size if it included designated wetlands (or something like that).