Moving an image in editor reuploads it as a new attachment, and sometimes corrupts it

Steps to reproduce:

• Create a page, with content "Hello World"
• Upload an image as attachment
• Add this image to the document at the bottom
• Move the image to the top using WYSIWYG editor

Expected result:

• The same image is simply moved at the request position

Actual result:

• The image is reuploaded as a new version of the attachment

On one occasion, the new version of the attachment ended up corrupted, but I have not been able to reproduce this behavior since.