What went wrong in this flight?


See flightaware.com/live/flight/DAL2 … /KATL/LIRF Delta ATL-FCO on Fri Dec 16.
The plane arrived on time; see also flightstats.com/go/FlightSta … =249198023 but for at least an hour it was forecast it would arrive 4 hours late. It couldn’t have made that itinerary and still arrived early.

Where can I get more info?