I haven't seen it, but I think it's not unusual for one to get to the door first and then lurk, and with William not there, it might have changed things - eg I've noticed that Edward and Sophie have been sent in after Andrew a few times eg it will go Anne, Andrew, Edward, but it seems to depend on who is the senior royal in attendance and the type of event. Without William/Charles, Andrew gets to default to his seniority, but when they are there, he's pushed back down.
Technically, if they were all there, it would go Anne, Edward, Andrew, Harry, William, Charles ie in reverse order of closeness to the crown.