This morning (07JUN) UA 872 from TPE arrived in SFO at 6:30am but passengers were asked to stay inside the aircraft until the official arrival time 6:50am. The reason was "flow control".
Flight from TLV arrived at 6am. Passengers from XIY and TPE got out of the planes around the same time (6:50).
I noticed that the arrival time of UA872 of past few days is always 6:50am. Never earlier.