I'd be interested to try this out.
I know of a few reasons we would show a VDN impacted. One is that there is no vector destination configured in the VDN, second when the Vector configured in the VDN does not exist.
From a Vector perspective. Vector down is when we recognized that the step logic will not complete successfully, or degraded if there are any non reachable/orphaned steps
However, it is not possible to add a VDN without mapping a vector to it(default is normally 1) or could it be the vector has no valid steps to progress the call ?