Router traffic not sourced from cluster IP address

Installation is VyOS 1.1.7.

Configured cluster and vpn per example at http://dc.org/files/Vyatta_HARef_R6.0_v03.pdf (starts on page 143)

VPN traffic at peer is coming from individual router IP instead of cluster IP address, thereby preventing VPN from forming.
Upon further investigation, any pings made from this router to another use the router IP as the source address of the traffic instead of the cluster IP address.

Is this a bug?

What good is a cluster config if the traffic is not going to originate from the cluster IP address? If it’s not a bug, I must be missing something very obvious, but I have researched for hours and can’t find it.

Please advise.

set vpn ipsec site-to-site peer y.y.y.y local-address ‘x.x.x.x’
Did you try setting x.x.x.x to vrrp address ?