I've been typing directly into the HTML view in the editor for a while, and someone else just tried typing using the WYSIWYG view. The editor is wrapping new lines in <div> tags rather than the default <p> tags. So instead of copy outputting like this
<p>This is one line.</p>
<p>This is another line!</p>
it's doing this:
<div>This is one line.</div>
<div>This is another line!</div>
It's breaking the structure of the site. Anyone have any idea why this might be happening?