Re: Weird outlines in my game
I don't have any experience with this kind of issue and as they are cc/mod related, it's always best to ask in the place where you downloaded the stuff or at a modding community (modthesims or sims4studio).
That said, it might be related to this issue: https://answers.ea.com/t5/Technical-Issues-PC/The-Sims-4-CC-Hair-Blonde-Streaks-Bug-FIX/m-p/5069642#M62885 so maybe the fix there helps you as well.
Maybe someone else has other ideas too.
