Has anybody has this error before or knows how to resolve it? It's happening more frequently and I'm really not sure what's causing it. Sometimes it just one hand, sometimes it's the whole body. It continues into CAS as well. I've been troubleshooting my mods for ages, and messing around with my graphics settings but it's still happening. I thought if somebody else has had this issue you might be able to save me more hours of frustration!

Thank you in advance!

Have you tried to repair your game in origin? What you can do is use the sims4studio and try batch fixing your mods folder

when my child aged to a teen all her clothes went t transparent, she has no CC on just Island living clothes/hair, makeup, not sure how to fix this

What about her skintone?
if you have any skin replacements it might be your culprit..

Yep dodgy CC. Apparently the new Island living (mermaid form) has caused lots of CC like eyelashes, skin and skin tones, overlays etc. to cause this issue. Most are waiting for a batch fix from Sims 4 studio.