If UUID is configured as the only primary lookup key, and a computer is defined and a job scheduled against it, the PXE server doesn't boot it to automation, or it does boot to automation but then reboots and gets stuck in a reboot loop.
In some operating systems and PXE clients, the UUID is reported differently (known as big-endian vs little-endian). The PXE Client might see the UUID as 01-234-567-89 whereas WinPE (and DAgent) will see the UUID as 10-432-765-98 (examples simplified).
The DAgent has been updated in Ghost Solution Suite 3.0 HF1 to identify UUID the same way PXE does. Upgrade to GSS 3.0 HF1.