I just saved one sim from Grim after she collapsed from freezing. She was on the street in front of my sim's house and my sim convinced her to group up. It would take too long to walk back to my sim...
When I made a previews picture I immediately turned of weather effects. Sim in pink hoodie turned from blue to her normal skin tone ( she is the wife of the male sim who froze to death yesterday, but I revived him with MCCC), next moment this happened. https://i.imgur.com/lzJ40S2.png
I'm turning off weather effects until it's fixed. No more experimenting.