I haven't been flying eco on SK longhaul since the refurbishment of the birds, so I can't tell if it's still the issue, but I would be surprised if it has changed. That last row often don't have full recline, and the last couple of row tends to be slightly narrower than rows ahead due to the tail section of the plane being narrower than the middle part. It starts from where the middle seats goes from 4 to 3 seats. In this section you also easier bump your heard against the aircraft sides if you are at a window seat. This is due to the aircraft body having a smaller diameter in this section.