Steps to replicate the issue (include links if applicable):

• Go to https://en.wikipedia.org/wiki/Open_access#Diamond/platinum_OA
• Open any image
• Press "Back" in the browser

What happens?:
Nothing

What should have happened instead?:
The image should close

Other information (browser name/version, screenshots, etc.):
Chrome

Details
This happens precisely when there is "/" in the URL fragment and doesn't happen otherwise. Probably MediaViewer confuses "/" with its own fragment (like /media/File:Open_Access_logo_PLoS_transparent.svg).