Thank you for the information.

Intermittent issue are always challenge to troubleshoot

We may have to check the ClonePrep / Customization log inside the agent machine to find the cause of the issue.

The OS Optimization Tool should have taken care of removing the Appex Packages which might cause customization timeout issue.

However, we still need to look at the logs for the actual reason.

Also check in VC if it get the valid IP address and DNS name. If not you can follow the KB: https://kb.vmware.com/s/article/2147129