Pure Storage FlashArray does not present LUN0 externally, it is a phantom LUN. Pure Storage - as with other vendors - use LUN0 on the back-end so that initiators can perform various SCSI commands before actual LUNs (Volumes) are provisioned. LUN0 is not visible on the FlashArray GUI.
Seeing LUN0 from our HBA management software confirms that zoning is correct. LUN0 has SCSI peripheral qualifier set and it is of SCSI type Unknown or no device type (1Fh) so that the operating system does not display.