Expected behavior

When opening an existing Post in the editor, and just exiting the editor without modifying anything, should just leave things as they were.

Actual behavior

For some posts, opening an existing Post in the editor, then just exiting the editor (both Aztec and Visual) triggers the Post saved on device snackbar and marks it Local changes in the Posts list.

Steps to reproduce the behavior

1. pick a Post that has images and videos in it, and has been written on the web admin (wp-admin or Calypso)
2. open it in the editor
3. exit the editor
4. observe the snackbar appears, and the post is marked "Local changes" in the Posts list.

Tested on [Google Pixel], Android [7.1.2]