I have a reservation, made through AA, that contains two Finnair segments (and several other AA and BA flights).
When trying to select seats for the AY flights I get that, for the ORD-HEL flight "they cannot currently be made online" (fair enough), but for the HEL-KRK flight I can actually click the "SELECT SEAT" button, which brings me to a seat map picture where all the seats are greyed out and therefore non-selectable (see below).
This has been the case for over a month now.
Does anyone here have experience with what is going on in such cases?
Yes, this is reminiscent of yesteryears issues with "optimal seating" and the introduction of seat selection fees. It may or may not be related to what you are experiencing, but here is one thread about it from the past.
most rows blocked from advance seat reservation
And one old thread relating to AA and seat selection:
https://www.flyertalk.com/forum/finn...emerald-5.html
Suggested workaround is to use customer service for seat selection.