We monitor our Hyper-V deployment via WMI and I've got this problem where on occasion, the interfaces just disappear in Orion. Stats collection stops on them and they never re-appear, but they are obviously still on the servers. A rediscover doesn't help, but a manual "List Resources" shows them there and they have to be selected to start working. Whatever the WMI equivalent of the ifIndex is must change, too, as they create new interface IDs in Orion and stats are started anew.
Anyone seen this odd behavior before?