I had the same issue back in April, LHR to IAH, so nothing to do with date lines
There were 4 or 5 messages communicating a delay getting progressively worse to 12 hrs (which would have made a 34 hr journey into 58!), before confirmation that the flight would, indeed, be on time.
Luckily all the messages came through overnight whilst I was asleep so I made it to the flight.