Yeahhhhhh, this explains why I CONSTANTLY ask my Sims to clean out spoiled food from the fridge. I thought the fridge was bugged. No, they're dropping it out of their queue!
I asked one of them to clean out the fridge and then get leftovers, and instead he ate the spoiled food and got sick. :P (From now on only the Sim with the Fresh Chef reward trait is allowed to cook in that household!)
I'm playing in an 8 Sim household (okay, two of those are pets) and without antilag mods they won't do anything. I usually spend all my time pressing the spacebar to check in on each of them and the space bar is unreliable as well, but I've found that taking items out of their personal inventory seems to help with that so it's probably unrelated.
It's really frustrating, guys. Without the antilag mods they basically stand around for hours staring into space while I spacebar between them. I finally turned off autonomy for the selected Sim and followed each Sim I actually wanted to do something around until it was done. I guess I have to watch each individual Sim go to work or else they WON'T DO IT, they head towards the door and as soon as I stop looking at them they go Research Carrot Plant or something, GRRRRRRRRR!!!
I kind of have control-freak-y tendencies where my Sims are involved and feel like the only acceptable reason for a Sim to drop an action out of their queue is their death. I'm frequently amused by what they decide to do when I'm not actively directing them so I don't like to turn autonomy completely off, and also no autonomy doesn't even help this bug. I tried it. They still stand around stupidly staring into space and dropping actions from their queue unless I'm actively staring at them.