In a Wordpress draft, paragraphs clump together after saving

In a Wordpress blog (latest version) installed on a separate domain, whenever I write a draft and save it, paragraphs clump together.

So, if I write
paragraph 2,
after saving, it will be paragraph1paragraph2.

It does not actually occur every time but every second time or so. I use the Enter key to make paragraphs. There are no <p></p> tags in the code and I would hate to add them. I use Windows 7 and Chrome.

Any explanation?