Sometimes, my sim does a very short T-pose and reset their action queue after digging in a dirt pile. I'd say this happens 25% of the time, and is more likely to happen when my speed is at level 3. There is no last exception logged.
This is happening since the dirt piles were released in game, I think with the cats and dogs expansion? I reported it before on the old bug forum, but nothing ever happened with it.
Edit By crinrict: Adjusted Title to fit old bug report.