What would cause my Nion N3 to display and extra octet in the MAC address? 00:0c:80:3e:80:0e:5a , this should be a 48-bit not 56-bit.

Whomever was entering it probably just fat-fingered, or momentarily forgot how many octets there should be in the MAC address.
Give me a call when you are ready to fix it and I'll walk you through it.