Cron fails to import new items

This is probably something dumb, but I can't quite figure it out.

Witness http://drupalchix.org/feed-item/42.
It is pulling from the feed at http://twitter.com/statuses/user_timeline/2789291.rss.

The last node was "Ok, let's find out if this works... tum te tum.."

But it should be " And once more for good measure."

I'm having inconsistent results with the Refresh tab too, even.

I'm using the SimplePie parser and tried setting down the cache settings to 1 second but that didn't seem to solve it either.

Any tips on troubleshooting this would be greatly appreciated!