Confused with drivers image

I've been messing with sysprep/images lately.. typically when I think
i've finalized a base image, I will sysprep it.. turn it back on, boot
to PXE..create an image from it. This image has no drivers other than
NIC card on it, fyi. I'll then "restore" the driver-addon image
manually which puts all drivers for the pc in c:\drivers , i'll then
boot the machine to find out that after going through the sysprep
process, no drivers have been installed. Upon further investigation,
there is no c:\drivers!!

I can't figure out the reasoning, but sometimes the c:\drivers gets put
there, in which case all is fine, drivers install, etc. But sometimes
c:\drivers doesnt get created when I restore the driver addon. Is
there some trick or certain scenario when you restore an image it
pretends/looks like its all fine but then doesnt restore?

I've seen no errors reported at all. doing it all manually from the IMG
command
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