Boeing told investigators that the Large Cargo Freighter, which will have a maximum takeoff weight of about 800,000 pounds, weighed about 633,700 pounds at the time it passed the Cessna on final approach to the airport. It is expected to be certified with a maximum gross landing weight of 575,000 pounds.
So why was the LCF 58,700 pounds overweight on approach? Part of the certification tests?
I couldn't say, but that's what I would guess, and the article didn't say that the LCF touched down....could have been touch and go or goaround.