So after a failed and protracted support ticket with Solarwinds - which they failed to resolve our issues - the tech was clueless we are stuck with an unreliable and unusable NPM 2019.4 HF5.
The situation that we have is random and intermittent - essentially our snmp v3 and snmp2 nodes are changing from "could not poll" to "interface x has state warning" to "one or more interfaces has a warning" to "polling normal" every few minutes , this is happening over nearly 400 nodes of different vendors and models.
Has anybody encountered this sort of issue before ? - The tech got us to delete and recreate the "SDF" files and that was about it.