I've had it happen to me probably a half-dozen times or so. It's usually because there's a special character in your text that's throwing everything off. Characters that I've had trouble with are certain quotation marks, the extended dash "--", some single quotation marks, superscript numbers, etc. Even though when you paste from a source these characters will often not appear, I they're still lurking and prepared to mess up your post.
The solution I've found is to see where the break occurs, edit the post, and delete the characters in the vicinity of the break. I then just rinse and repeat until it's good to go.
- Christopher
