Animation fails after scaling some bones

I have some animations for my character. User can change some body parameters of character (breast size, waist size etc.), in script this is implement through scaling specific bones. Idle animation stops when user changes parameters. But when I start playing idle animation after all parameters changed, mesh returns to its original state, as if parameters were not changed. Could I solve this problem somehow?

The values you set in Update are overridden by animation. You should apply your parameters in LateUpdate (which happens after animation update), this way you’ll be able to apply your parametric scale on top of animation.