Allegedly, on or about 26 November 2013, AP sent:
I am using extra privacy options in the Firefox but not in Opera. Sometimes I use Opera also and other times Firefox. In Firefox, I am using the addons like NoScript, AdBlock Plus and Better Privacy.
It's still missing the headers. Give the other browser a try, and we'll see if that change things. Likewise, you could try changing some of the privacy settings. There's little point in trying to be extremely private with email on a mailing list, you're posting in public with your email address. Perhaps they give you choices for certain websites against others (I'm only familiar with NoScript - it does let you customise it).