Interesting! You're right - it seems to be wrist accessories and earrings that cause this.
The Sims I had in my library all had an accessory on.
The only exception I've found is one of the new Horse Ranch tops - which does it over base game etc and new pack items - Sim is new and has no accessories - see attached screenshots
I would be curious to know if this is by design or not tbh. Because it looks like but I've had this issue too.
I'd suspect not as for that top you can see the patterns of the top of jeans for example under it. If it was by design you'd see a flat top.
Also - to add to the original bug - if you put too many 'accessories' on the head of your Sim it causes the same thing.
The limit seems to be 3x.
I was having all the shirt untuck when I had a more than three of eyeshadow, eyeliner, lipstick, cheeks, along with hats and earrings.
So, for example: if I had a hat, I could then only do eyeshadow and eyeliner - if I added in lipstick the shirt untucked.
Or, I could only do 3 make-up types.
Didn't happen with every shirt (which made it even odder) - but it did it enough that it was frustrating!
And it did mean that with the new expansion I couldn't create a Sim with one of the new hats, earrings, a full face of makeup and a shirt tucked in!
