An odd situation last night is prompting this question.

DL 173 SEA-JFK was, according to both the iOS App (before boarding) & onboard FA, supposed to come in to JFK T4's B30. Upon landing, the pilot tells us that we're going to be pulling in to T2's C60, but there's a plane in the gate already. We then proceed to wait nearly an hour until he comes back on the intercom and says that we're going to go to T4's B30 instead (where we should have been going to in the first place).

So - is there a maximum ground hold time after arrival by DL policy, or are pax just expected to deal with whatever poor arrivals-management procedures are in place?