I've got this exact problem on Xbox series S. When Sims hug pets. It looks exactly on mine as it does on Simrissie's photos. It's been going on randomly for many months. Sometimes with arms forwards and stretched out at strange angles. Sometimes their arms are behind their backs. With the pet in their arms or sometimes the pet doesn't move.
It's mostly with pets but it's happened with Sims a few times too. Say greeting loved ones. Surprised it's not been addressed yet but I could say that about numerous bugs at this point, reporting them is taking half as long as playing the game for me. Still, we love our Sims... wouldn't want a hug from one though!
This has been happening to me also for a long time. Dogs randomly become demons, it's so creepy, I'm surprised I haven't seen a topic about it before this.
But also this that petting them often just glitches. I don't have any mods, it happens very randomly and while petting both cats and dogs.
If I remember correctly, the pet interaction yeah (these have happened during a long period of time). Sometimes my sims also do this autonomously but I think they usually go for the pet interaction.
