Having this exact same issue, but only with my mermaid sim for some reason. All CC is disabled, cache is cleared but It didn't seem to make any difference. Needs don't turn yellow/red when low and don't show up as negative buffs. All of my sims (Not only mermaids) also keep peeing themselves whenever they wake up!
Something I noticed: When my Sim is at home, the bars act up. When she goes to, say , the gym and works out, gets a drink, takes a shower, etc. the bars work fine, for a few and then start acting up at the gym too. If I go back home, they work again, but only for a few tasks and then start acting up again. I have tried this with no mods/CC and it still does it. Definitely NOT a mod issue.
