[EDIT] After a lot of digging around, I found out that the problem was in how I integrated the CKEditor into my page. The simple and obvious way does work in this c
You need to prevent the default submit action and then resubmit the form yourself manually:
$('form').submit(function(e) {
e.preventDefault();
// do your processing
this.submit(); // call the submit function on the element rather than
// the jQuery selection to avoid an infinite loop
});