I'm not sure how many people play with their active sims autonomous, but I generally do because I like to spend time individually and would rather my other sims not just stand around occasionally cheering or giggling to themselves waiting for me to get back to them. (I'm not much of a multi-tasker)
Anyway, I am having a strange issue where I will set my selected sim up to do a few things and in the middle of the queue he/she will run off to do something completely random and cancel out my queue. And without it even showing that's what they are going to do! The first few times this happened I didn't think much of it because it was a toddler who needed to be changed/held/fed and I just thought the game was naturally overriding me for this purpose. It seems that often toddlers and babies can do this to your active sim, at least in my experiences. That's fine, babies need attention.
But it's been doing this for all sorts of random things. Most recent example was I sent an active member of my family (by marriage) to go home to visit his folks. I queued him to to chat with his parents but he would do one or two of the things I suggested and in the middle of it all he'd run off to get in the hot tub and it would not even show that's what he was doing until he was actually IN the hot tub! He did this twice in the middle of conversations with both parents! It's not like there isn't a hot tub at home (that he has never gotten into autonomously) but he was apparently really wanting to soak! haha
His moods and needs were all full so it wasn't a stress thing and again, this was just one example, I've been having this occur a lot more lately in many of my games with random sims doing as they please regardless of what I asked.
Is this just a "deal with it dude" type of thing or could something be wrong that I need to correct?
Mods installed: Overwatch, Error Trap, MC, MC Cheat, MC Intergration, Portrait Panel, Saver, Story Progression, Traveler, Decensor, and more entry points (for the schools)

Welcome to the Sims where your active and inactive sims will make your jaw drop, pull out your hair and make you want to slap them silly.
Sounds pretty normal at least in my experience tends to go in spurts.

Deal with it, dude.

Actually, you might try to find a way to keep some sims in some circumstances from doing what they seem to be so insistent on. If the toddlers and babies are fine already and don't need to be picked up and held quite so often, lock them in a room with stuff (for the toddlers) to do and only grant access to a primary caregiver. I often do this when non-related guests come over for a visit.

When couples with very strong relationships visit, especially out of towners (by way of Traveler connected worlds), in my game many of them seem obsessed with woohooing with each other. That's sweet and everything, but not always what I had in mind for these visits and I've had more than one unexpected autonomous Try for Baby sneak in on me that way. I can't lock them out of all the bathrooms with showers necessarily, but I can lock them out of bedrooms and areas with other woohoo friendly objects that they don't really need to be around. It usually seems to be beds and showers they head for, though.

On the hot tub, fence it off and lock the gate? In this case you might end up with your sim footstomping in front of it, sometimes sims can still "see" what is not really available for them to do.

I play with high free-will all the time and yes I do notice there are sometimes interruptions with the queue and my Sim deciding to do something else not yet shown. I have also seen this behavior when nothing is in the queue as if to delay its presence temporarily so I can't cancel it out before they begin the interaction.

But this is nothing new and even Sims in The Sims (2000) are meant to have a mind of their own and do not always take instruction from the player. This is also where free-will comes into play which allows the Sims AI to sometimes bypass the player's input for whatever reason.

Now I'm imagining igazor's active sim household inviting a nephew to come and visit from out of town.

nephew: ''I'd love to, and if it's alright, there's someone special I'd like you to meet. I think you'll really like—''
igazor: ''That's great. You two are sleeping in separate twin beds, and you're sharing a bathroom with your grandfather.''

It seems like everyone who plays TS3 has an in-game object or two that their sims just can't resist. Common culprits include the deep fryer and snow cone machine (no surprise there, art imitating life and all), there seem to be some random ones like the rocking chair, and in my game at least, it's always the sprinklers. So much so that if I leave a sim with the Loves the Outdoors trait alone for even a minute, there's around a 90% chance that they'll autonomously want to play in the sprinklers, no matter how many fun and expensive toys they have, inside the house or on the lawn. Fencing doesn't help—I've actually had a sim force-reset on me when she couldn't get to the sprinklers, as she just kept trying over and over and waving her arms and stomping her feet until OW decided she must be stuck.

Usually, though, I see the action in the sim's queue beforehand. The only exception I can think of is when someone tries to pick up an infant or toddler without my direction. So I wonder if your wandering sim is responding to some unseen offer from another sim, the same way toddlers seem to be able tell an adult to pick them up. If, for example, some other sim wants company in the hot tub, they could be calling yours over without you knowing about it. Or maybe the game's just being weird again, I don't know.

By the way, after patiently listening to my whining about the adults constantly insisting on picking up their kids, igazor suggested that a DebugEnabler reset would clear the queue without otherwise messing with the sim. It works like a charm. Now whenever I see any sim, active or otherwise, doing something I don't like, DE takes care of the problem. My inner control freak is beaming with pride. So is my outer one.

Igazor - some great suggestions! and ugh!! the Sim foot stomping! (almost as bad as the video games music) I give most of my sims the neat trait which is great for keeping things tidy, but OMG -- "Yes, someone else took the plate!! It will be okay, calm down!" LOL I swear sometimes family meal-time sounds like a nightmare! Between the clearing off of the table or if I get a bottleneck at the main dish when calling to a meal.

Thank you to everyone! It's nice to know it's just a thing. Though it does get frustrating. I posted once here about one of my main sims who never wants to sleep but prefers either naps or coffee. LOL She has no traits that would give you this impression of her, but there it is...gotta put her to bed myself about 80% of the time!

Puzzeladditct - that's what I think too about the toddlers, it's as if they demand to be picked up via telepathy and it's not even about food or being dirty much of the time because the sim will just stop whatever and go pick them up and stand there. Of course there's pets...don't you dare have a pet because the babies will get ignored more than half the time so the cat can play laser. haha

I love this community, everyone is so kind and fun, it's such a stark contrast to some places I visit. Looking forward to the new site. Got all signed up today.

@puzzlez - Now let's not get carried away here, I'm not talking about separate single beds and bathrooms. I'm talking about guests jumping ship, so to speak, to woohoo during/after every meal, during every television commercial, at every pause in the conversation, and sometimes breaking into their own established action queue to do so. I don't always watch the out of town grandparents like a hawk when I think they're going to be amused for sim hours teaching their grandchildren how to talk/walk or are reading them stories, often enough my attention gets pulled away elsewhere and then I might have a surprise on my hands.

For those who might need it, on the DebugEnabler solution to clear a sim's action queue, both the visible and hidden kind, so that they are once again doing nothing, that would be on the sim, NRaas > DE > Options:Sim (or Smartphone) > Object > Reset.

@JohnL - Yr dum n yr mudder looks like a llama. Feel more at home now?

LOL @ igazor. I got made fun of about how "stupid" I was more than once, but after the worst one I had to come back. (silly of me I know, cuz I normally leave it be) Of course it was on Steam. I simply pointed out (not so nicely and a bit graphic) that they didn't enter this world knowing everything about computers and neither did I.
It's likely I could talk circles around them on a number of other subjects, (can we talk astronomy?) So IDK why I let it get to me, but it did. Everyone has a breaking point! AHH GABBA ZEEEE HUH? LOL

I used to see these things more whenever I ended up on high free will or ot got changed to high by mistake and I just go to options to turn it back to low if I ever find it's on high now.

Can't really help with the subject but I've had that happen a couple of times, too - and it was exactly with the hot tub. There was no action in their queue so it couldn't be cancelled, you could just watch them as they trekked around the whole house to the backyard and into the tub. I don't remember if their queue got stomped - I think the one time it was still there they just ignored it and did their thing. It was pretty weird and I never found out what was causing it.