Deleted image selected as a cover image still is visible in preview

Steps to repeat:
1 Click create post
2 Paste title and tags
3 Type some string inside the content box of the post editor
3 Put an image to the content of the post editor
4 Select this image as a cover image
5 Delete this image from the content box of the post editor
6 Submit the post

User can see in the list of the post the image preview of the deleted image but default image preview should be.