Group policy is not being applied to the Symantec Endpoint Protection (SEP) mobile users
Web Security Service
Even when the general SSL interception is enabled on the portal account, the default behavior for mobile traffic is to not be intercepted for SSL inspection.
For group policies to work, SSL interception has to be enabled for mobile devices. You need to change rule #3 in the SSL interception policy (Portal > Service > Network > SSL Interception) to intercept mobile traffic.