Hi Paul,
Yes, as I mentioned, if you do network changes, Guest Customization is supposed to be run (if enabled). But it should run only minimal (so-called "reconfigure") flow. That would only reconfigure NICs and "computer name", so it shouldn't cause you any problems.
The issue you're hitting is that Guest Customization runs the "full" flow. That's wrong and needs to be investigated.
/Andrii