I'm having an issue with custom post fields under a custom post type with built in custom post fields. The theme came pre-built with them. I've entered data into them, namely a thumbnail image, and a full-sized image, and they show on the page just fine.
However, I go off to do something else, and I come back and my custom post fields are gone with no thumbnails showing on the page and no full-sized images. What's going on here, and is there a way I can get around this?