I'm quite baffled by this issue and I have absolutely no idea what could be causing it. I have a Wordpress website that has been working fine, until for some reason, the admin panel started to screw up and wouldn't display all of the CSS correctly. Upon further investigation I found that the load-scripts.php and load-styles.php are loading with odd characters, as you can see:
This is basically a default Wordpress install, and I have reuploaded that file, yet the problem persists. It doesn't seem to be a character encoding issue, as the headers say it is UTF-8.
Here is the kind of scary part, if you remove all of the get attributes from that URL, the page displays:
I won't navigate to that site because Safari says it is malicious. But how exactly could this be happening? Why would that URL come up? The code in that page has never been edited.