Extracts the MAC address from an Adafruit Feather M0 Wifi board

GetFeatherMacAddress.ino

#include <SPI.h>
#include <WiFi101.h>

/*
GET FEATHER MAC ADDRESS
Jeff Thompson | 2017 | jeffreythompson.org

Extracts the MAC address from an Adafruit Feather 
M0 Wifi board.

NOTE!
Due to the way Arduino's Serial print commands work with
hex values, the MAC address may not include leading zeroes
on some values. If you get a single digit (ie "F"), just
add a zero in front (ie "0F").

 */


void setup() {
  WiFi.setPins(8, 7, 4, 2);

  Serial.begin(9600);
  while (!Serial) {
    // wait until connected
  }

  if (WiFi.status() == WL_NO_SHIELD) {
    while (true);
  }

  printMacAddress();
}

void loop() {
}


void printMacAddress() {
  byte mac[6];
  WiFi.macAddress(mac);
  
  Serial.print(mac[5], HEX);
  Serial.print(":");
  Serial.print(mac[4], HEX);
  Serial.print(":");
  Serial.print(mac[3], HEX);
  Serial.print(":");
  Serial.print(mac[2], HEX);
  Serial.print(":");
  Serial.print(mac[1], HEX);
  Serial.print(":");
  Serial.println(mac[0], HEX);
}

Any idea why this would print

28:2:0:20:AC:7F

When the MAC printed on the chip is

F8:F0:05:E7:C0:42

?