Exercise for Mr. Burns quest.
Looks like the new update in the App Store fixed it. Double check, but looks promising.
Forum Discussion
This is also happening with Legs and Louie 1hr "Interrogate a Squealer" task. I'll start it, close the game, and they'll be both walking around not on a task when I go back to it. Seems to only happen to tasks that involve props with the animation... Barrel, bike, mechanical bull.
