Try removing all your mods (move them all to another folder for now), deleting "localthumbcache.package" (had the wrong file name before, sorry!) in the Sims 4 Folder in Documents, and then testing with a vanilla save? (You don't have to give up your current save, but make sure to name the test save something else!)
mods get outdated with patches though and you need to make sure everything is still working with the current patch level.
Try a backup of your save game to find out which of your mods potentially cause the issue, then when you found them, check for updates.
Here's a list of mods that broke with this patch: https://simsvip.com/2019/02/21/broken-mods-for-february-19-patch-strangerville-gp/
The list is not necessarily complete.
@pinksapphire10 : Don't worry, you have nothing to worry about as far as that's concerned. 🙂
Deleting the localthumbcache.package (which makes the game generate a new one when you play it; sorry I had the wrong name before, I was going by memory both times) is good practice whenever you add, remove, update, or change mods so that nothing is stuck in memory in your game that can cause problems.
Thanks StarryMight. After I replicated your steps, in Edit in CAS I updated with only non-customs/non-mods, like basic hair style and dress that came with the original game. After I clicked the check-mark, non of the updates were reflected in the live game. Looks like I am with the same problem. :/
