Podcast art doesn't sync

In the Library tab of iTunes - the artwork is clearly there and shows up for each podcast on the left side.

But on the Unplayed tab, 3/4 of my podcast downloads dont sync with the art. Even if one day I screenshot/update the art, it wont sync the next day.

Even stranger, sometimes the art will show up for a particular episode while its downloading - then disappear once its done.