Back Float doesn't increase energy level
I'm currently playing a challenge where I only control one sim and the others are completely autonomous. I have had 2 sims now that when their energy is at critical level they go and back float rather than sleep then they end up drowning as the back float does not increase their energy level. I have mods installed and am on PC. I've now disabled back floating through MCCC but I would expect their energy level to increase if this is what they are choosing to do when tired otherwise it shouldn't be an autonomous action.
This thread in the bug archive refers to a similar issue.
[OPEN] Auto-solving energy need causes 'Back Float' instead | EA Forums - 11410164
If you haven’t already done this, try also testing by moving the whole mods folder to another place, delete the localthumbcache.package and then test to see if the issue remains without mods/cc there.