In one of our environments we have over the last few days experienced issues where VMs mysteriously had their Network connections changed to a different port group on a vdSwitch. When we leave at night the VMs are accessible and operational. during the night at some point several VMs (up to 5% of the environment) have had their port groups changed. There are no Tasks or Events that show anything but in some cases several DRS vMotions. Going to the VM logs also doesn't reveal anything as well.
There seems to be nothing in common across these VMs other then the same vdSwitch.
My question is, is there any other specific logs or messages within that logs that would show a change from one port group to another.