Cache Storage persist only until user closes Safari

[beingcompiled]

Is there still no workaround for this issue in iOS 12.1?

"Problem: in iOS 12 cache in Cache Storage magically disappears"

or

“Safari and the home screen shortcut share the same Service Worker registration (but not the instance) and the cached files. Safari View Controller (such as the In-App Browser within Twitter) supports Service Workers and the cache but it seems it’s deleting all the data after the session is closed.”

:_(