artofproblemsolving.com is broken, doesn't happen with vanilla Firefox
Looking at the console I see:
Loading failed for the <script> with source “https://assets.artofproblemsolving.com/js/jquery.min.js”. c6h586004p3466382:94:1
her'es a test url: https://artofproblemsolving.com/community/c5h1151720p5452658