All images appear twice in custom post type, but not in pages or posts

Every time I “insert image into post” it gets set as the featured image also, so that it appears twice in the post. This does not happen on my regular pages and posts… only on my custom post types. I have a feeling that it is a setting that needs to change. Any ideas how to fix?

Also, can an image from a url be set as the featured image for a post?

Thanks!