I had a sim freeze to death inside a spa (the one that comes pre-built with Spa Day) during cold weather the other night. I was playing with mods & CC turned off since the patch. It was Malcom Landgraab working as a massage therapist. I'd set the spa in Newcrest and it was Mystery Weather Day so it's possible it was only cold and not freezing by the time the camera focused on him freezing.
a week ago
I noticed my sim was chilled while in the basement. I thought that bug was back but she stayed chilled when I sent her up to the living room. I also noticed that in Sulani, a sim was swimming with blue skin from being chilled. It was hot and it was outdoors without a thermostat anywhere. So, they got chilled somewhere else and stayed that way. The only way I could get the chilled moodlet to go away was to cheat it away.
I haven't played in a few months so I don't know if this is a recent problem or not. It wasn't there last time I played.