That actually worked, despite it saying "Enter your FINNAIR booking reference". Interestingly enough it also said that "frequent flyer number could not be added", which is strange because it does show up in my confirmation e-mail. So I'm guessing it didn't show up in the app in the first place because for some reason my AY frequent flyer number couldn't be linked to what's in the Iberia ticket.

On Android, refreshing seems to be a bit random. I've found that going back and forth between a few different screens, and pausing for a while in each one, will eventually refresh it. A simple "refresh now" button could make sense here.