Okay, so this has been super annoying:
So, I have this married couple. I moved them into a brand-new house. While exploring the Outfits option when I clicked on them, I noticed the "Change into Nude" option, which I had never really tried before. So, I clicked it. (I did the same for the husband too, but then quickly changed him back.) The husband looked at his wife and gasped, as to be expected. But the thing is... when I changed her back into regular clothing, he would still do it. And the interaction comes up as "See What's Happening". The same thing happens for neighborhood/NPC/other sims as well. They stop what they're doing, look at her, and gasp. It's been super aggravating because if they're in the middle of doing an important task, they'll just stop and do this. ((Also, the wife is pregnant in the 2nd Trimester. Not sure if that matters or not?)) I've removed all my mods, as well. Is it because she's pregnant, or maybe it's something else??

This still happens!!!!! This happens with my sims who have gotten naked in front of others before. Even if they are fully clothed they look at them and gasp.

My sims do it after Woohooing (Really after what they just did why are they embarrassed!!!!) I am not having the problem you are. I am guessing it stemmed from a mod that even though you removed them the glitch has remained in a save. Have you tried making another household to see if other sims you are playing do this?

Yep... I have an all-girls household and this happens to one of them. But it doesn't happen to the point where they can't function, unlike with the other household w/ my girl and her husband. I also have another household with a gal and her gf... her gf will look at her and gasp even if she has clothes on

What you could do is take out your save and tray folder put it somewhere safe like your desktop, then uninstall Sims 4 and reinstall it again then put back your save files and tray files. that should stop this.