I have tried installing the demo of Pimcore 4 and 5 and both had the same issue - the cache buster’s URL were returning 404 but all other URLs were working correctly (static files and pimcore routes).
One example URL with 404 is this: /cache-buster-1529940980/website/static/lib/magnific/magnific.css
What may be the reason? It is a new VPS server which uses cPanel and WHM. The support told that the web server is nginx 1.15.5 which uses reverse proxy to HTTPd 2.4 and the httpd executes PHP scripts trough PHP-FPM server.
EDIT: This renders the frontend broken. The backend is completely functioning.