Sen. Elizabeth Warren’s (D-MA) campaign is facing a labor complaint filed by a Sen. Bernie Sanders (I-VT) supporter who is focusing on the campaign’s use of its confidentiality agreement, which prevents staffers from making “any statement that may impair or adversely affect the goodwill or reputation of the organization.”

The Colorado-based Sanders supporter – who does not work for the Warren campaign – filed the complaint Tuesday in hopes that it would shed a light on what he claims is a gross violation of the National Labor Relations Act. The National Labor Relations Board accepts and reviews complaints by individuals, even if they do not work for the organization in question.

According to Bloomberg Law:

The Aug. 13 challenge to the campaign’s non-disparagement clause was filed by Jason Legg, a tenant’s rights attorney in Denver, Colo., who supports Sen. Bernie Sanders (I-Vt.) for the Democratic nomination. The National Labor Relations Board accepts charges even if the filer isn’t an employee of the organization alleged to be violating federal labor laws. … The filing against the Warren campaign by a non-employee who supports one of the candidate’s challengers suggests that both unionized and non-union campaign operations could continue to deal with complaints over issues that are fairly novel in the political campaign space, where unpaid volunteers, confidentiality, and long hours are the norm. President Donald Trump’s 2016 campaign faced claims of labor violations that were dismissed by the NLRB in early 2018.

Legg told Bloomberg Law that he hopes people “think about the substance of the charge” rather than his support of Sanders. He added that Warren is his second choice.

“I can’t say I’m not at all politically motivated, I’m a Sanders supporter and Warren’s my second choice, so I guess this is one way to show the contrast,” he said.

An unnamed individual hit the Sanders campaign with a labor complaint last month, listing allegations of retaliation, repudiation, interrogation, discipline, and discharge. The complaint followed mounting pressure from Sanders field organizers, who complained of making “poverty wages.” While Sanders initially floated capping employee hours in order to fulfill the $15 minimum wage commitment, both parties eventually reached a deal.

“We made an offer which would have addressed that problem several months ago; it was rejected,” Sanders told CNN following the deal. “We underwent negotiations. It has now, the offer, it has been accepted.”