Thanks ITGirl. I've been activating Windows via KMS. Here's my process for Windows 10:
Install Windows 10 Enterprise via USB.
Install custom software: Browsers, Office, etc.
Windows Updates, Activate
Go to Microsoft Store settings and disable automatic updates and "show products on tile"
Then, to prevent any updates from occurring in the background, I disconnect the machine from the network, and remove all (?) UWP apps with this Powershell script:
Get-AppxPackage -AllUsers | Remove-AppxPackage
(This would be when I would capture the pre-sysprep image, but I've been skipping this to see if I can get it to reboot after sysprepping)
Sysprep: sysprep /oobe /generalize /reboot
Occasionally it will reboot into Windows setup after running sysprep, but I could never reproduce it reliably with a captured image. It just boots to a blue screen:
"The operating system couldn't be loaded because the system registry file is missing or contains errors.
File: \Windows\system32\config\system
Error code: 0xc000000f"