Query the list of configured nodes from corosync at startup.
When the cluster starts, Pacemaker may not know about all possible peers. As a result they those peers may not be fenced appropriately - even though they are known to corosync.
Result (if any):
All nodes listed in corosync.conf are recorded in the Pacemaker configuration and any that have not been seen by the time the cluster obtains quorum will be fenced.