I had a flight back in feb IAH - LAX; flight was delayed 2 hours? iirc and we were notified at least 3-4 hours before hand.
Arrive at the airport, they move it BACK to on time, which was now in about 10 minutes.

Only to then have boarding time come and go by about 20 minutes before it got changed BACK to delayed.

Boarded an hour late, only to have to de-plane due to mechanical.
Still got into LAX though around 1am