I am playing on Steam Deck.
Prior to 1.2, I had all romanceables at 10 hearts (locket given + all events viewed). I married Semeru.
After 1.2, all land-dwelling romanceables remained at 10 hearts and their hangout events were accessible, but Miranjani and Denali went down to 8 hearts and checkbox for the locket is unchecked (even though we were dating prior to the update). After viewing their hangout events, I tried to give them the locket again, but I got a message that we were already dating.
If the developers intended for us not to get non-spouses to 10 hearts after the update (which I understand), then the land-dwellers are bugged and they should have been demoted to 8 hearts as well. But if they are okay with us having 10 hearts with everyone, then the merfolk are bugged.