Tbh, I'm not sure exactly what you have going on. All I can tell you is that I haven't seen it happening in my game. I also use mods btw. So I'm inclined to think it is being caused by one of your mods. So I would begin by looking for something like a CC slider, default replacement or other mod like MCCC that affects the body shape just to make sure everything is up to date. It might be worth it for you to start a testing save and test out your mods there rather than in your main save.
Since this is recent, it may be that you downloaded something new recently that is the culprit so I would look at those first. Another thing you could try too is to delete the localthumbcache file if you added or removed mods and cc recently.
Hope this helps.
I don't have any custom content except for MCCC and I tried running the game without it and had the same issue (I even completely deleted it to grab a fresh download afterwards). And I've deleted my cache and thumb-thingy file a million times since yesterday. Okay, twice, but still. It no helpful.
It's weird - I haven't noticed the sliders changing at all. The weight and muscle mass remains the same between the body shapes (though depending on the body, they still look drastically different). Nor have I noticed in changes to facial details. It's strictly just the body.
Ok, so mods except MCCC. I use it too and don't see the issue. But I will take another look to see what is happening with my sims.
In the mean time, the only thing I can think of for you to try is to repair the game.
Hope this helps.
Edit. I just looked at sim bodies in a vanilla save and in my modded main save. What I found leads me to think that maybe the templates do change as you play depending on how you play. They may just be a starting point when you make sims but idk for sure. Things like exercise, overeating, reward store potions, the Weight of the World and Taste of Diet ice creams, and GTW serums can all visibly change a sim's body in game and it appears that the body shape reflected in CAS matches their current appearance as closely as the game can as far as I can tell. I haven't noticed any changes while I play other than what I made sims do that changed how their body looks so I'm at a loss as to what is happening in your game unless you are doing things that would change how the sim looks like exercise, overeating, etc.
Hope this helps.
