Preview not showing up for Articles ?

I bunch all my reviews up as Taxonomy terms 'Review' so they all show up in one long list for browsing.

There is usually a preview of at least the first few lines of text within the article when viewing them all together in a list, However the preview does not appear on my Urban Solive ?

It sometimes show's up, but often as soon as I edit the article it just disappears and I'm left with just the Title, Submitted by... & The Tags ?

What is happening ?

Here is a pic to show what I mean :