Hi alterego,
I've got the same problem. The answer you've given is not a full solution.
When: Cluster1 has Node1(active) and Node2
I monitor Cluster1(which is now Node1) and Node2
When it fails over to Node2 the following is the result:
Cluster1(which is now Node2) and Node2 are monitored.
This means i've got Node2 monitored double and Node1 is out of the monitoring interface.