One of my cloned machines was having trouble until I changed the SID with New SID from Microsoft.
The others didn’t appear to have any duplicate SID problems but having them appear in the WSUS administration webpage was still a challenge.
The administrator is also able to classify machines into different groups and select which updates will be available to which groups.
In doing that, sysprepping his original source image wasn't in his list of steps.
That being the case, some of the registry keys specific to Windows Update that sysprep clears were inherently not cleared properly.
One of the most frustrating problems I have run into when installing WSUS was an installation in which most of the computers in the organization were not showing up in the WSUS console.
My GPO was setup correctly and WSUS was running, but most of the computers were simply just not showing up.
I've checked the install, and it's set to all computers (Install, Inherited).