[kh99]

It doesn't look like 25 chars, but maybe you've changed it since posting? In any case - the RSS2 feed contains a description and content. The description is plain text and is cut off at the "Thread Preview Length" (defaults to 150 chars) unless &fulldesc was specified on the url. When you look at the feed with the first link you're looking at the "content" part which has the full text.

I'm not sure how to fix it - can you specify "&fulldesc" on the url (or is that 2nd link someone else's site?). I suppose you could edit the file external.php and make it always include full text for the description, but I don't really know a lot about RSS feeds so I don't know if that's a good idea or not.