Qube receives traffic from host interface?

I just noticed this and it worries me. I run a VPN gateway qube that gets its traffic from sys-firewall. While using it, I have an iftop session open to monitor traffic. I set the VPN qube up according to the community guide, so it supposedly has a kill switch.

I noticed that the VPN gateway was receiving traffic from my host interface. iftop was showing the IP address assigned to the host interface by my router. How can the VPN qube get this address? I thought it was held secured in the sys-net.