Seems that you have some inconsistency in DB. Do you have this duplicity also in [Nodes manger] or [NetFlow Sources Manager]? Or it's only NTA problem of resources? It you can see this duplicity also in our managers, just delete appropriate node.
If it's problem only with resoruces, please contact our support and provide us diagnostic. I will look at it.
I see what you're talking about - I had the device in the NPM database twice under different IP addresses. removing the extra instance cleared up the problem.