Can only get 1V from D0 pin

It’s the weirdest thing. I’m using a Photon Internet Button.

I’ve reinstalled the firmware, reflashed tinker, and have been able to flash code to it from the online IDE so it seems like it is working fine. But when I go through the beginner tutorial for tinker where you just try out the digital and analog write for pin D0, all I can get is 1v (checked it with a voltmeter). If I used D1, it works perfect. And the rest of the tutorial works fine, I just can’t get D0 to give me more than 1V.

Do I just have something set weird or is this something unique to the button?

AFAIK, the piezo buzzer is attached to D0 on the Internet Button.

If you do analogWrite(D0, 128) you may hear some buzzing