XenMobile Server 10.4 fail to start main app after applying rolling patch 3

I’ve come across an issue with XenMobile Server 10.4 failing to start main app after applying rolling patch 3 (RP3)

Scenario:
Clustered environment with two members
First server patched successfully from 10.4 to 10.4 RP3
Second member reporting a fail after attempting to start main app for an extended period of time

Solution:
You have to patch one node at a time.
i.e. patch first node to RP3, restart and shut it down. Patch second node, restart and start first node.
If you already have a node running that is patched to RP3 other nodes will not start while it is running.