Muscle tone not properly displaying in CAS and live mode

I wouldn't claim it's 100% the same. The situation is like this, and it's a bit complicated.

I've got Sims who have maxed their muscle mass and have no fat in the live mode. When I upload them to my library, and then put them in the CAS, they look normal. But, when I start a new game with them, their muscles are totally not shown in the live mode.

But, if I put them from my library into the CAS, and "move" the muscles slider up (their muscles slider is already at the top, and their weight slider is fully down), they get about 50% reduced muscle mass in the CAS, although the muscles slider is still at the top, and CAS doesn't register it as a change. And when I start a new game with them, the muscle tone is now properly shown in the live mode, although it is reduced like 50% from what it should really be.