Harvest [usually] submits counters with the same names as defined in Data ONTAP, and always in lower case. I think the counters you refer to might be from the 'external data provider' feature of OnCommand Performance Manager (OPM). By default OPM uses a graphite root of 'netapp-performance' so if those metrics are in that hierarchy it also points to OPM. I have seen some oddness with some of these specific counters in my lab (also 8.2.3) when using OPM as the datasource and logged bug id 951548 for a fix. Since OPM is a supported product I would open a support case for the issue and mention that ug id 951548 could be relevant.
Storage Architect, NetApp EMEA (and author of Harvest)
Blog: It all begins with data
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