I noticed something when I flew through Athens recently. When I check in online or through the app, I am able to see the full list of available seats. Same is true if I go back and try to modify the seat selection. However, I noticed that when I use the kiosks at ATH airport, a lot of seats that show up as available on the app/online are being greyed out on the kiosk. So, for example, instead of showing me 30 available seats, it just shows me 10, where the front of the cabin is full and the available ones are towards the tail of the plane. I am Gold, so there shouldn't be any need to not allow me to select certain seats, so the only other thing I can think of is maybe load balance issues where there aren't that many passengers and they are trying to distribute them evenly across the aircraft. Has anyone noticed this? Do you have any explanation for it?

P. S. This happened both on my outbound and inbound visit at Athens airport, so it wasn't a single occurrence.