Really wierd thing just now.
I setup two custom post types using all the same parameters. "Reviews" and "States".
Both worked fine, and displayed the content fine on all pages.
I was trying to add a featured image to one of the "state" pages, and all of a sudden all state pages are now 404. "Review" pages are still fine. I've compared all settings on both, identical - as is all structure and it's the exact same type of content.
How do I troubleshoot this? I've reset permalinks several times.