A KSC report is basically a list of resources with a graph and a time-span.
The resource ID is built depending on org.opennms.rrd.storeByForeignSource.
By default the resource format is:
if storeByForeignSource is enabled, the format is:
Now, no matter which format is being used, if the resource doesn't exist either because the node was removed or because the RRD directory for the resource was deleted, the KSC report is going to throw an exception.