This afternoon, while at lunch when I mentioned my looking forward to my first time at Flagship Dining in a few days, my cousin, who flew from LHR to LAX via JFK in F, said that Flagship Dining was closed at JFK on Tueday Jan 4, around 1PM when he was there. It was also closed at LAX yesterday prior to his flight at 11AM.
The Flagship Lounge person at JFK told him it was because of being understaffed. He didn't bother to ask at LAX.