You can't have perfect artwork and good animation every episode. There's a trade-off, when the animation is better the frames are not drawn as well. The animation was good this episode, when you pause frames it'll almost always look awkward (except for the really poorly animated episodes, where the characters are almost always still and hardly move at all). While the anime isn't top quality, especially recently, it's not nearly as bad as people make it out be. When you watch an episode trying to nitpick, of course you're not going to enjoy it.