Caching Issue on Firefox Mobile

Hello everyone, we have many websites hosted with GoDaddy and a customer brought to our attention recently an issue with their website (rcopinc.com) in regards to caching with the Firefox Mobile application. The issue is that after making changes to a page the changes do not show up when using Firefox on my Android or iPhone after refreshing, opening and closing the app, etc. With the iPhone after about half an hour the changes seem to come through but even after a week the Android version still doesn't update. For the changes to show up I have to clear my browser's cache. We cleared our server caches as well which didn't help. We have a caching plugin WP Rocket which we disabled for our testing, and we managed to disable the built-in GoDaddy caching for a little while using FTP before it recreated the files we renamed. Even with both of these turned off the issue still exists. We asked WP-Rocket about it and they said it was an issue with our HTTP cache headers. WP Rocket automatically sends the correct headers (max-age=0, must-revalidate, no-cache) but they suspect GoDaddy's Varnish servers might strip these headers. We have contacted GoDaddy about this and are trying to escalate this issue as it is almost definitely an issue with their servers. Worryingly, the bug seems to apply to all our Managed WordPress websites. Has anyone had any experience with this issue? Any advice would be greatly appreciated, thank you!