WAF Virtual webserver error since 9.5

For a long time i had a great working setup in WAF for my 2 webservers and exchange webserver.

I created 3 real webservers and several virtual webservers. a combination of HTTP/HTTPS and internal/external traffic based on the interface.
This setup works for over a year without any issues, until i updated to UTM 9.5.
Since then as soon as i activate the virtual webserver, the "Site path routes" becomes in error. On the TAB "Site path routing" the matching path sais  the Real webserver is in error.
I searched the log for any clues, but it doesn't show anything unusual. I deleted all the rules in virtual and real webservers en started new with 1 real and virtual webserver, but still the error persists.

Does anyone have some ideas where i should find the solution of my issue?

Best regards,
Hans