I’ve made another test. I’ve puted the same interface on my Test instance on another server. Then, I’m not abe to reproduce the issue.
The line on NagVis give a value every minutes. By the way, it seems the value in Nagvis are not sames : 3Mbs on NagVis against 30Mbs on graph, like a x10 delta.
So it seems the problem is linked to my Prod instance. I keep searching.