Gosh, I have it as well and completely forgot to report it when I first saw it. The last few weeks I've been playing a save file in which I don't use laundry at all, hence my lack of memory. I hope it gets fixed soon! Thanks for notifying the moderators.
I have an interesting data point for this bug:
my saves had this issue (old and new ones) until this morning. I updated my Mac to Catalina and that caused me to clear out my Sims 4 folder and only add saves back. Since then, the animation works as it should, no more strange overlap.
So it might be a case of a cache file somewhere being stuck with the glitch.
October 2019 - last edited October 2019
Sims will now hold laundry bags the right way. What is the right way, you ask? Trust me, it’s better than how they were holding it before.
Fixed in Patch 1.52.100
.. or not
Funny enough, it worked just fine before the "fix". It wasn't broken before that patch. Now the laundry bag gets attached to their hip. As far as I can tell it affects all sims age teen and up, no matter their occult status.
Should be said that the problem is only with dry laundry. They hold wet laundry correctly. At least for me.
And if it matters: I'm on Win7 x64.
Product: The Sims 4
Which language are you playing the game in? English
How often does the bug occur? Every time (100%)
What is your current game version number? 126.96.36.1990
What expansions, game packs, and stuff packs do you have installed? All, as of 29th October 2019
Steps: How can we find the bug ourselves? Have a left-handed sim pick up laundry, and go to wash it.
What happens when the bug occurs? The sim makes the correct hand gesture in their dominant (left) hand, but the laundry bag is attached to their right hand, and is held strangely.
What do you expect to see? The bag should be in the left hand, in the same way as it is when a right-handed sim does laundry (right-handed sims don't have this problem).
Have you installed any customization with the game, e.g. Custom Content or Mods? Not now. I've removed them.
Did this issue appear after a specific patch or change you made to your system? Neutral/Not Sure
I tested this vanilla, and the issue was still around. It looks super freaky, and it's been a thing for a while iirc. I'm not perfectly sure when it started, but I'm p sure it was before the last patch. It might've even been before Island Living, but I couldn't say for certainty.
Right-handed sims are completely fine, they hold it normally. This issue is only with left-handed sims.