I opened up LJ this evening to find that the posts it's showing are out of sequence -- the top post on my friends' feed is from yesterday sometime, and there's a later one further down the page. It isn't most recent comment, either: both of those are from an account that turns comments off on crossposts.
My conclusion is that either they're using some kind of ranking system which they're not telling us about (and which I didn't see any setting for that that might fix it), or possibly that crossposts are arriving weirdly out of sequence. So...
PSA #1: If you're posting on LJ and not DW, or posting different content on LJ, I might not see your posts.
PSA #2: If you're crossposting and redirect all your comments to DW, I'm going to stop reading you on LJ to cut down on clutter. (If you allow comments on LJ I'll still go over there and read them, if I can find your post. That is, obviously, no longer guaranteed.)