@alienco Reimaging is completely unnecessary. The problem is with the bios/firmware settings not the target OS.
The snarky answer is don’t let the FOG server go down or become unavailable.
A bit more realistic answer is change the boot order so that it boots from the hard drive by default in bios. Then when you want to image the computer, have the imaging tech sit in front of the target computer and press F12 or F10 while booting to get into the uefi/bios boot manager and pick pxe boot from there. That is how we do it on my campus. I require the fog tech to sit in front of the computer they are imaging. This avoids accidentally reimaging the CFO computer during quarter end close (it only happened once). So normally under this methodology the computer always boots to the hard drive and the exception is to pxe boot during imaging only.