Group Mod message not being sent to switch in groupbasedpolicy Proof of Concept demo

Following the steps in this wiki page:

https://wiki.opendaylight.org/view/Group_Policy:Building_and_Running

We see that one of the vSwitches receives all of the flows, but the other is short 2 flows. The flows that are missing refer to Group flows, and the problem is that the group flows don't exist, so the flow mods are rejected. Further investigation revealed that one of the vSwitches isn't receiving the group flow mod messages from the controller. We've also verified using the msgSpy and Jconsole that the counters indicate that the group flows were received by openflowjava, but don't get sent on the wire.