[IL] [AA] Mermaids swimming in human form when in custom venue roles

I created a venue role that filters for mermaids. I verified that the Sims filling the role are mermaids. However, when these Sims swim in the ocean in Sulani, they have human legs instead of mermaid tails. This save file has never had mods or CC and my mods folder is empty. I used the "Water Activities" activity to get them to swim.