Ok I got it and I can see the issue. The issue is when you add a view that holds a edit post form and you add that view within your post's body and then you try to change the featured image the media uploader is broken.
But I wonder why you add those view with post body, you should create a content template for the posts and add whatever you want to display within that content template and remove all those content from your post's body (views and other blocks) and add it to content template you design to display your post.
I cannot use a template because every post is different and the view are inserted in the middle of other piece of content like text, images. More over I use more than 10 views that can be called depending on the subjects and what I need.
I have another website with a Cred form called in a view, but the view is inserted directly in the post template. It's working very well but for this website the view is always after the content of the post. It's not at all the same things.
I think I will disable cred it will be easier and I will use a simple edit button to fix this issue.
