The meaning of 'volunteer' must have changed lately, at least at the NYTimes, as evidenced by this paragraph :
His savings are gone. He lives with Ms. Olinger, who makes $10 an hour as a volunteer coordinator at a food pantry, Harvest Food and Outreach Center, where they also get groceries every week. It is her salary that pays their rent.
From this article :
Am I a volunteer at my job? Well, I voluntarily go in most work days and I voluntarily collect my paycheck even though I have other options such as being out-of-work and and without any income.
Yes I am a volunteer worker!