I don't have any recent experience, but over the years I know they happen.

At LAX TBIT, the big board drops info for arriving flights after 1 hour or so. Obviously, many passengers can't make their way out in an hour. And greeters often know to come late. If a greeter arrives 50 minutes after scheduled arrival and the flight arrives 25 minutes ahead of schedule, the greeter will never see any info on the big board (as the info will have dropped off before the greeter arrives) and therefore has no way to determine whether the passenger is delayed by C&I, as many foreign airlines often provide no way to find out by phone or even internet of actual arrival time.

At the other terminals, it's even worse. I've seen UA monitors dropping their own international arrivals after 15 minutes! (No one can come out this soon!)

Flight tracking websites won't help, as they can't provide GATE arrival info.

Although there are other ways to find out the info nowadays, just what purpose do the boards or monitors serve when the info goes away before the passengers emerge or even before the greeter arrives? (And it's safe to say that on international flights, a majority of passengers have checked luggage and can't just "go right through" C&I.)

Is this just LAX, or elsewhere in the US too?