I get this often with almost every task, it does not happen often enough to be annoying but it does happen when cleaning dishes, reading, using the computer, I was unsure if this was a bug as well as it could just be tempermental sims.
Does it happen while you do it or to interactions that are queued ?
When this happens in my game I'm usually able to trace it back to three things.
1) My mood changes. For example: My Grandpappy takes a brisk shower to get energized, I suggest he goes to perform an energized box, in an effort to comply he walks into his secret agent room and his mood changes to confident because of all his confident decor and the energized box is either removed from queue or he stops boxing mid-swing. I can still queue up a normal box.
2) The other sim I'm interacting with has a schedule cut off I can only assume it's a job or curfew. For example: I will commonly queue up several social actions with a sim walking down the street. They will typically stop and wait for my sim to get to them. Occasionally though my target sim has to be somewhere urgently and walks away so the remaining queued interactions are cancelled. This seems to be completely based on the other sims schedule. For example: Summer Holiday is typically walking around the neighborhood in the morning and early afternoon but once 4:00pm hits she leaves and not only are the remain interactions in queue cancelled but I can no longer queue up any other interactions with her.
3) I switch to another sim in my household and the original sim has some urgent needs to take care of. For example: Grandpappy in his old age cannot hold his fluids like he used to be able to so if I queue up a lot of actions with him and then switch to my other sim he will frequently be found using the restroom instead of doing the things I asked him to. This is all a matter of autonomy.
None of those instances are bugs so if this does occur due to a bug I have been very lucky thus far. The only time I've had an interaction queue and bug out was related to painting. My sim was feeling very flirty and I tried to capitalize on it by painting a flirty painting. However I had to select the action four or five times before it finally accepted it. The first time I walked over to the easel and got charged the 100 simoleons but no canvas ever appeared. I tried four more times getting charged each time. The fifth and final time the canvas appeared as normal and away I went. I believe between the fourth and fifth times my sim got bored and started walking off so it may have been a routing issue. That has only ever occured once. I'm chalking it up to a random and rare routing issue at this point.
