It is not the server that does not send multicast packets but the client that does not send them. In practice, the app that needs to connect to the iTunes server sends mDNS multicast packets, but the Android system on your device doesn't forward them to the VPN interface. I think this problem is due...
You're welcome. I checked the results of the tcpdumps you sent me and the Android one doesn't have mDNS multicast packets. I've done some testing with the Android emulator and the multicast packets are forwarded just fine, so it seems that the device you are using is not forwarding the multicast pac...
I think it's better if you use the tcpdump on the server side, because the tcpdump requires root privileges and so on Android you have to root the device
unfortunately this information does not help.
Perhaps you can try to capture VPN packets with a tool like tcpdump and check the differences between Windows and Android VPN...