Originally Posted by
coolfish1103
1. All the seats were taken by Elites (that is possible cause 359 PE cabin is small).
2. Your flight may be adjusted again back to 333 or another aircraft (so system block).
Thank you so much. It was indeed the second explanation. They kept the same aircraft (A359), but they blocked the seats because they have recently started to sell the seats as PE. But I was lucky and could change the booking and switch the second leg of the flight from Y to PE for a nominal fee.