So every now and then I'm trying to add a new device into NCM.
As far as I can see, the device has added in to NPM via SNMP and polling seems to be ticking along. Then when I go to add to NCM, in edit properties I get a popup that says something along the lines of: "Can't verify as not responding to SNMP" which requires an OK, and then a further click of submit before saving.
If I then re-open edit properties and try the SNMP test it fails.
However, as I say, to all intents and purposes polling is doing its thing, collecting stats, etc...