XEM6310MT JTAG Voltage

The XEM6310MT User’s Guide implies that VCCAUX is tied to 3.3V in the table on page 12. Yet the BRK6310MT breakout board shows the JTAG header VREF pin is tied to 1.8V. Question - is VCCAUX really 3.3V and if so why was the JTAG VREF tied to 1.8V?