I have a weird problem. the_excerpt() returns the entire post on posts and pages, but shows correctly on category views and on the home page.
I have the Advanced Excerpt plugin (http://sparepencil.com/portfolio/advanced-excerpt) but the same thing happens even if I disable it.
I have a featured area in the the header.php that displays on every page, the problem occurs there. The site uses the Magazine news (http://magazine-news.com/) theme, if it makes sense. On their demo page it works fine.
What are the possible scenarios for this to happen?