Ideas
I'm having this issue as well. I'm on PC with mods/cc but it happens even when I remove all mods/cc. Almost all situational outfits on walkby and service Sims include some sort of headwear that's clearly incorrect for the current outfit/situation. The big bow in the headgear category shows up the most on both male and female Sims. A couple of my Sims just completed the temple in Selvadorada and the MALE Temple Guardian skeleton appeared wearing that big bow! So ridiculous looking and immersion-breaking. I have MCCC installed so the game imports 100% of NPCs from my own library and they *should* have their own saved outfits/traits/etc. This was working fine until the July 1st update and since then, the game still imports NPCs from my tray but it changes their outfit to include rando hats - especially that big bow.