SEP 12.1.2 Firewall blocks UMTS traffic

Hey there, anyone experiencing problems with UMTS connections and SEP firewall on Windows 7 clients since they've updated SEP 12.1 to SP2?

We are facing an issue, where Windows 7 clients which should connect over UMTS sticks while they're not in internal LAN getting their traffic blocked by SEP firewall. If we deactivate the firewall, it works like a charm.

The whole thing worked with SEP 12.1 SP1 too... on XP machines it is still working, even with SP2. No policies where changed though.