I have a site I've recently migrated to a new server. Everything is mostly looking okay, except on existing posts: when we go back to edit a post, and edit media attachments within it, the "Edit Original" and "Replace" buttons are missing.
The file URLs are all correct, and on the server, permissions of both the files and the parent directories are the same on both servers.
If I add a new image to an old post, it works fine; it's just trying to access the buttons on the existing images that's a problem.
Working, old server:
Not working, new server: