Thanks for doing that.
To get this finished, I’m going to lock the bootloader manually. But the script should still be fixed.
The ‘Lock your bootloader’ section on Fairphone’s support article to do with managing the bootloader says to do fastboot flashing lock_critical before fastboot flashing lock, evidently because the ‘Unlock your bootloader’ section of the same article says to do fastboot flashing unlock_critical as well as fastboot flashing unlock, but as I was following the /e/OS installation guide I just did fastboot flashing unlock, so logic would dictate that it is sufficient for me to do fastboot flashing lock without doing fastboot flashing lock_critical.