I've noticed that in 0.28.3 and a few recent prior versions, when I click a search result to be downloaded (or an RSS item - even automated ones) - they're not always added to the queue. I often need to add items twice, or after a delay. Occasionally, the option to download is grayed out.
Also, I've noticed that searches often stuff up, and the RSS can't be quickly refreshed. I suspect these problems are all related to handling of RSS requests.
Tested on fresh XP 32 machine (in a VM), Vista 32, Vista 64.