sometimes they will be shown as chatting to another Sim. the overhead bar shows, but the active Sim is sleeping, for example. but now that i think of it... i can't be sure if the queue bubble gets stuck. just need to test again.
(edit: when a Sim is dancing and that action is replaced with "listen deeply", i've seen that "dancing" will not clear from the active tasks.
"listen to dramatic story" gets stuck once in a while, often when another (inter)action is queued after it. if that happens, a white bubble showing two silhouettes close to each other appears, instead of one that shows a Sim's face, and it remains in the active tasks section. the interaction is not taking place anymore, a different one is, but it still won't clear.
"resume (recipe)" also gets stuck from time to time, but not that often as the above. they have already finished cooking and eating, and are doing something else. clicking on the bubble to "cancel" this not-ongoing action doesn't make it disappear.
another one is "go jogging". it often remains even after cancelling it and having Sims do something else.)
