For what it’s worth, it’s happening to me too…and it’s seriously pissing me off. I’ve gone in and unchecked the option to have WordPress ‘helpfully’ correct what it determines to be badly nested XML, and it’s still putting </object> tags where they don’t belong.
Worst of all, it’s not doing it consistently. When I save the post, it leaves it alone. When I reopen it again and save again, THEN it throws them in.
