There is another issue with webkit: When using it in portrait mode there is no text reflow (right-hand margins are cut off), and so it is not possible to read articles without reverting to landscape.
Or maybe the specific source for your theme colors could be causing the problem?
Not sure I am seeing that, but I do see that "expired" articles are still in the feed, even from many days ago. Which begs the question: what does "delete articles after 24 hours" actually mean, if after 72 hours old articles are still there?