@xshirlanax
I've seen this before but on females. And in my my case, it was a default replacement upper body mesh causing the issue. So, it is most likely a cc or mod issue that got broken by the last patch. Probably a mod since a ton of them got broken. But best to be sure it's not something gone wrong in the game first.
So first thing I suggest is to create a new vanilla game in a separate The Sims 4 folder without any mods or cc. Just move your current folder to the desktop or another safe location outside of the Electronic Arts folder and start the game. A new The Sims 4 folder will be created by the game so no worries. Then go to CAS and see if the problem is still there. If it is, then you will need to do a game repair and try again so see if the problem clears up. If the problem is not there in a vanilla game, then it's definitely a cc or mod issue.
So back to your original The Sims 4 folder. The most likely culprit causing your problem is a cc shirt but it could be something else too like a custom skin tone that uses a custom mesh or a default replacement. The last patch did give us nails so I would check any custom default replacement feet meshes you have just to make sure they still work. And it could be more than one thing. Or if you use any mods with built in default replacement body parts, it could be those. So I would look at those things first. There are several ways to go about it. I would test mods first and if no problems are found, then move on to cc.
The 50/50 method is the usual way folks do it but I find that the quickest way is to start moving (or copying) things over to the vanilla game mods folder a little bit at the time and see if the problem shows. If not, then move the items you tested out and and move some more over and try again. Just keep going until the problem shows up again. Then just narrow it down to the file that is causing the problem and remove it. But keep going until you've tested everything you have though as more than one thing could be causing the problem. Test everything!
Hope this helps.
