No "swim" option for merfolk sims in the ocean

My sim is a merfolk, he cannot swim in any beach or ocean. Oceans are not anymore clickable. There's only "wade here" in some areas. I once teleported a sim in deep water, he just stands there, fully clothed, not doing anything. The "draw on sand" option also gets cancelled as he cannot reach it. But he can swim in the pool. I have repaired the game, reinstalled the game, reinstalled all add-ons, deleted cache, deleted mods, made a new save, created a new sim. it worked for a while after the reinstalls, but it's back.