When a poller looks for vmware custom performance counter (vmware.hv.perfrcounter and vmware.vm.perfcounter) data and founds empty counter without data, it assumes that the counter was just added and its data has not yet retrieved from vmware service. So the request is ignored until the data has been gathered.

Howerver it turns out that there can be counters without data. Such items must be handled and marked as not supported with appropriate error message.