incongruence dns set in ssl portal with those present on forticlient clients

Hello everyone,

i am writing to you because we have a strange problem about the dns of the vpn ssl. In the menu SSL-vpn setting we have specified the following dns to use: 172.1.1.20 - 172.1.1.30, unfortunately we have noticed that all the clients connected through forticlient inherit completely different dns, that is: 172.1.10.50 - 172.1.10.60. is there a way to understand why they take different dns although we are configured explicitly in the portal?

dns configuration in attachment, do i need to open a case or do i have do control something more specific?

Regards