No DHCP - Really Strange
One a few PCs we have troubles with PC’s taking their image, some do, some don’t. When the ones that fail after booting iPXE and then the FOG menu it seems they will not get an IP from PXE after a reboot. Not sure why, they just got one and are able to get one in windows. It’s like once something goes wrong, it won’t get an IP again. It just gets no offers were received.
What kind of switches do you have? Do you have VoIP? Do you have other tftp servers?
On the switches within your environment, do you have Spanning Tree Protocol turned off as recommended? Do you have portfast enabled for cisco switches?