Parece que o carregamento do conteúdo da página muito longa está duplicado
Tentei mudar para o modo de segurança e encontrei este erro no console:
_service-worker-8605e5c2e133a2a05d9dd2906cb8e959e59d9071ee2958ed83b143cf451c9a23.js:3 Uncaught DOMException: Failed to execute ‘importScripts’ on ‘WorkerGlobalScope’: The script at ‘https://domain/javascripts/workbox/workbox-sw.js’ failed to load.
at https://domain/service-worker.js:1:14
(anonymous) @ _service-worker-8605e5c2e133a2a05d9dd2906cb8e959e59d9071ee2958ed83b143cf451c9a23.js:3
A bad HTTP response code (404) was received when fetching the script.
register-service-worker.js:22 Failed to register Service Worker: TypeError: Failed to register a ServiceWorker for scope (‘https://domain/’) with script (‘https://domain/service-worker.js’): ServiceWorker script evaluation failed
Após uma pesquisa, um erro semelhante foi observado neste tópico Service-worker redirection 403, que estava relacionado a um CDN mal configurado, se isso ajudar de alguma forma?