This node stuck forever in compatible mode of master election. This means that it does not sent its version in heartbeats. And also it ignores versions sent with heartbeats from other nodes. Thus in unfortunate case if this is a master it will be impossible for the newer node to take over the mastership.
Unfortunately the reason why the node stuck in this state is not completely clear. It removed itself from the list of nodes supporting versioning when it apparently received a notification about the node list change. And the list did not contain the node itself. But the cause of such notification is not known.