"Disk User" Showing up on EFI boot screen after a clean install with APFS Encryption

Hi, I am hoping somebody can help me.

I did a clean install of High Sierra,10.13.1 on my mid 2014 15" MBP, erased the drive using CMD+R, went in to Disk Utility, erased existing volume then created an encrypted APFS volume, then proceeded to freshly install High Sierra. After install, I now have this 'Disk User' user account showing up on the boot screen, then my actual User Account, then the Guest User account.

Everything seems to work fine and Disk Utility says the HDD is APFS encrypted, but I don't understand why "Disk User" is present on boot next to my actual OS account.

This is the second time I attempted a clean install this way, and I would rather not sit through another 4 hours of the install pain (each time it took around 4 hours to install, not sure why).

- Can someone please enlighten as to what has happened, did I do something wrong?

- Is there a way to correct this behavior, it doesn't seem like Disk user should be exposed in this way

I can't seem to find consistent answers anywhere else.

Thanks

P