That's all the error message in the JS: Uncaught SyntaxError: Invalid or unexpected token (at /modules/contrib/canvas/ui/dist/assets/index.js?v=1.3.2:610:186393) We use Varnish 7.1 on that server to serve all the static CSS and JS files. Could that cause a problem here? And this problem does not happen always, sometimes it loads fine for a few days and then the problem appears again until cache clear. With opening that index.js file in prod, I see a good chunk of the JS is missing after row 610. I checked that file in dev, it had 2554 rows.