It's not entirely clear if it's the agent fault or the website. I tried to use a RUC on a flight that said it had availability on website, but the agent said there was no availability and EF showed there was no Z bucket open. So perhaps it was website that was wrong. Perhaps there was availability in old OY bucket, but it's not really clear what the website was looking at. If there's availability in Z and it is also showing RUC availability, I would agree that it's most likely the agent who is wrong.