Thanks for reporting this. We’ll take a look when the team is back online. What browser/device are you using and is it happening on different browsers as well? Any browser extensions you’re using?
Just checked and it’s working on Chrome on my Android phone, though that uses a different URL (no ‘assets’ subdomain): https://wanikani.com/level_up_image.svg
Extensions: Ublock Origin, and Tampermonkey for a couple WK userscripts, that’s about all.
Thanks, I’ve downloaded your IP address and am hacking your mainframe now. If you give me $500 in Apple Store giftcards I can make all your troubles go away! /s