I received an update today from the Case I opened on this issue. The backline developers have identified this as a bug. Running Network Discovery with the VMWare protocal against your VCenter will delete a Guest VM from the NS if it discovers the Guest VM is no longer on the same Host it found it on from a previous discovery task. If you are using Asset/CMDB data with your Guest VMs it will be lost when the Guest VM is deleted out of the NS. In our case it was also causing an issue with the Site Server / Task Services. The Task Server was a Guest VM. It was deleted by the discovery task. Tasks stop working until the VM checked back into the NS by it's Altiris Agent update process.
An interesting note, our NS is a VM also. The NS deleted itself out of the database when the discovery task ran.
VMM , Network Discovery, VMWare , VCenter