I still remain with one problem which is sometimes if I open my PWA offline

white screen usually occurs when you are using ie11 or an older android <7 webview.

But I guess you are experiencing this blank screen in chrome?

sometimes …

Without any other info it’s like finding a needle in a haystack. You will have to investigate when this happens, and when not. For example:

it only happens the first time you view it offline. it only happens on chrome and not firefox ( yes some people have had issues with PWA’s on chrome lately) errors in the console when it happens. ect…

btw I have had zero issues with workbox 4.x and PWA’s

If you have an url or the pwa I could check it out.