One time we saw the misc it was suggested was there any chance there was a google account, passwords, or PIN left on the phone?
Other times, I know it seems unlikely, but a USB cable managed to do most of the fastboot commands in the script but fails at one late task.
Perhaps look at the whole USB chain. It has been reported that certain USB will not carry all complex fastboot commands. You will need a good quality (full capacity) data cable, so not a thin, skinny cable. Avoid USB hubs including any USB hub that might be hidden in the PC / laptop; for predictably good results check (if necessary with a manual) that you are connecting to a USB-2 port soldered to the motherboard.
Many times a USB-C to USB-C cable may be provisioned through a modern hidden hub not supported by platform-tools.
Similar case Installation of e/OS on CMF Phone 1 - #102 by PurpurPixie