issue with white screen WP fullscreen on mobile

I got an issue with multiple accounts. I have a copy of multiple account like [login to view URL] [login to view URL] [login to view URL] al accounts (folders) got there own WP installation and the same configuration including Super PWA. every website (folder) is for a different customer with there own subscribers. Only subscriber are able to use this website. NOW THE ISSUE when I loggin to a website as subscriber and logged in succesfully I can add icon to the homescreen. when starting the mobile website from the icon on homescreen to view site in full screen its often complete WHITE (you see only the time,WiFi, battery on top. this happens more and more and more. but not always. i use multiple icons on my homescreen and every time i switch to other mobile fullscreen page i got a white screen. ONLY MANUAL SOLUTION THAT WORKS The only solution to fix this problem is following these steps. iphone -Setting app -Safari -Advanced -Website data -Remove All website Dta -go back -Delete safari history Then launch website from home screen Login again Then it works HELP Does anybody know whuy this happends and how to solve this problem for me? Thanks