Interface Operational status Unknown

Probably need to do a list resources and re-add the nics.
When an interface goes gray in Orion it basically means that "we asked the device about interfaceindex #xx and the device didn't know what I was talking about."
It's pretty common for people to make changes in the hypervisor that effectively remove an existing interface and create a new version of it, under the covers in windows each interface has an index number associated. You end up having to remove the old interface and add in the new one, or sometimes you can get away with just editing the DB to give it the new index number, but the risk to that is if there are any other attributes on the interface that changed Orion might not notice.

Any chance you are using snmpv3? Could be something weird with the view assigned to your user that isn't providing access to the OID for interface status.