Interesting! We're going to start fresh sadly, sometime very soon.
One thing I noted when removing the cluster and re-adding it was that before, it had cluster name, then under that, the nodes listed separately. And we could click node1, see stats, then node2, different stats for CPU, memory, etc, and so on with all nodes. After re-adding it, it was simply the cluster name with no nodes listed under it. So it appears they changed the way it handles clusters in some version or another. And my guess would be that the issue we're running in to is tied to that change somehow. Only a guess of course
Glad to hear yours is sorting itself out without having to lose any other data!
I'll post back again to confirm that starting fresh 'fixes' it for us. How could it not though? New instance, new DB... if it doesn't, I'll really start getting concerned...