I have this problem too (I’m on a Mac… is it the old “CRLF must be right because that’s what Windows does” logic?), and noticed this misbehavior when I switched browsers from Shiira to Safari.
The worst thing is that I would be happy to just use Code view and edit my breaks manually, but every time I go into edit a post, it defaults me to Visual view and destroys all my paragraphs. Heck, I’d be happy just to be able to default to Code view, or to remove the Visual editor, regardless of whether the Visual editor can or will ever be fixed in this respect.
-Chris