Redirect

Because every image uploaded to WP has a URL (called an attachment url) so by uploading an image called quiz, you have inadvertently created a url already called Quiz, and there must be an seo plugin which redirects the attachment url to it’s image.

To fix, delete the image, rename it and upload it again and it should fix itself.

Ok that was actually it!
However I can’t create a page interfans.org/quiz when I try it becomes interfans.org/quiz2

how so?

That url is now “reserved”, I don’t know off the top of my head where to find it but you would need to delete that url from the DB.

If I had to guess it would be in _posts, look for the quiz row and delete it, it should be set as “attachment”… hopefully someone more knowledgeable than I can help with this part.