I also had this happen last year, although I didn't have the foresight (or inclination) to look on the app at to where my bag was. I'd had a particularly tight connection at JFK (last flight of the day) where I was certain my bag had gone astray.

Off I went to file a missing bag report. Upon reaching the baggage service desk they advised me my bag had made it and was due out on belt #11. Again after not much action, I decided to walk around the belt and there it was off to the side (someone had taken it off the belt).

My initial thoughts were as it had a heavy tag attached it was treated differently to most other bags. I later then assumed the short connection at JFK may well have had something to do with it - perhaps it wasn't containerised with the rest of the baggage and was loaded as a rush item in a different hold. I'm pretty certain the guy at the desk referred to belt 11 as outsized baggage. My bag isn't what you'd class as particularly large or out of guage so can really only put it down to one of these two things.
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