Another datapoint:
HEL-TXL-OTP-TXL-HEL next week. OW Sapphire (AY Gold) # is on the reservation.
I called the local toll-free number, connected to Romania (funny how she referred to TXL as "Berlin", but OTP as "Otopeni").
All XL seats were "blocked", so got regular aisle seat on 3rd row for the first 3 AB operated flights. The agent knew my status without telling so seat assignment was free of charge. 5 minutes on the phone.
I managed to self reserve exit row on the final AY operated flight online AY.