Insert image into post. Then click on image and bring up the image details modal. Choose "replace image". Then select a different image than the one currently selected, and click "edit image" in the attachment details sidebar. The wrong image gets loaded into the image editor. It always seems to load only the image that is currently selected in the visual editor, not the one selected in the media modal.
Note that the delete permanently link right below the edit image link does seem to delete the correct image. It's just the edit image link that's loading the wrong one.