Sims who have been best friends/enemies remain as acquaintances

Is this thread still ongoing? Because I have the problem of stuck acquaintances. My couple have been romancing with each other for quite a while. I wondered why they kept showing apology options and struggling to get an option to woohoo and then noticed that they were not marked as partners. Today they got engaged - it shows it in CAS and in their opened panels, but in the relationship panel at bottom right and when they are talking to each other it still shows them as acquaintances. My game is fully updated, no mods or cc whatsoever and I have almost all packs (a couple of kits missing). I'm on PC and have deleted the local thumb cache file with no difference.