www.vmwareadmins.com

After encountering a bug: http://kb.vmware.com/kb/1017861

we needed to go through and reconnect the interfaces on some VM's:

get-vm | get-networkadapter | set-networkadapter -connected:$true -confirm:$false

This happened on vSphere 4.0U1 in which this bug was supposed to be fixed, per: http://www.vmware.com/support/vsphere4/doc/vsp_vc40_u1_rel_notes.html

going to try to duplicate using a template that was created post update 1.

Time for a VMware support call!