Sen. Bernie Sanders (I-Vt.) delivers a speech at the Montalban theater in Los Angeles on July 25. (Etienne Laurent/EPA-EFE/Shutterstock)

An unnamed person has alleged to a federal agency that the union representing some employees of Sen. Bernie Sanders’s presidential campaign did not properly address a grievance, according to documents reviewed by The Washington Post.

Although concerns by some members of the Sanders campaign staff about the way management has treated them have been documented by The Post and other news outlets in recent days, the filing suggests a possible conflict between campaign staffers and the union leaders representing their interests.

“Within the previous six months, the above-named labor organization has restrained and coerced employees” who were exercising their rights, the complaint says, “by refusing to process the Charging Party’s grievance for arbitrary or discriminatory reasons or in bad faith.” The filing did not specify the grievance.

The charge names United Food and Commercial Workers Local 400, which represents rank-and-file Sanders campaign employees. It names the Sanders campaign as the relevant employer in the matter and an office address in Des Moines as the location.

The accusation, which was filed Thursday with the National Labor Relations Board, follows an allegation filed with the agency earlier this week against the Sanders campaign, which was first reported by Bloomberg Law.

It is unclear whether the same person filed both complaints, but they share common elements, such as the filing location — Bettendorf, Iowa — and the employer representative named in the complaint.

The union declined to comment on either of the accusations presented to the NLRB.

The NLRB is an independent federal agency that, among other things, investigates claims of labor violations by employers and unions. Anyone can file charges with the agency.

The NLRB is reviewing the claims to determine whether they merit further action or dismissal, a process that could take weeks or months.

The Post obtained copies of both charges, against the campaign and the union, through the Freedom of Information Act. The charging individual’s name and contact information were redacted.

The name of the employer representative on both charges is Brooke Adams, whose title is listed as deputy field director for Iowa. Adams did not immediately respond to a request for comment.

Jean-Marc Favreau is listed as the attorney for the Sanders campaign in both accusations. Favreau did not immediately respond to a request seeking comment.

Representatives of the Sanders campaign also did not immediately respond to requests for comment.

Both filings were submitted after The Post reported July 18 about an internal standoff over compensation between unionized field staffers and the management of the Sanders campaign. The staff had argued that the compensation and treatment they were receiving did not meet the standards Sanders (I-Vt.) espoused in his public rhetoric.

On Monday, union members voted to approve a pay raise — bringing the annual salary of field organizers from $36,000 to $42,000 and extending their workweek from five days to six. The agreement also clarified that the field workers were expected to work 50 hours a week but could work more if they wanted. It was unclear whether the deal would be enough to calm workers’ complaints for the duration of the campaign.

Sanders made history when his campaign announced in March that all employees below the rank of deputy director would be represented by a union, UFCW Local 400. The union and the campaign reached a collective bargaining agreement that took effect May 2.

The agreement was ratified, however, before the campaign had assembled its sprawling roster of field organizers, low-level workers on the front lines of voter contact efforts. Eventually, field staff expressed concerns about pay directly with Sanders campaign manager Faiz Shakir, according to a review of internal communications by The Post.

The document filed earlier this week with the NLRB against the Sanders campaign alleged that the campaign discharged, disciplined or retaliated against employees for reasons including joining or supporting a labor organization and engaging in protected labor-related activities.

It also alleged that the campaign interrogated employees about union activities.

At the end of the filing, the charging party included additional information in support of the claims, including accusations that the campaign “failed to notify us upon hire” that there was a collective bargaining agreement and that it violated the agreement by requiring additional workdays.

That earlier complaint hinted at a forthcoming action against the union. “The Union did nothing” to address the issues with the campaign, it says, adding, “I will be filing a DFR against them.” A DFR often refers to a “duty of fair representation,” which is what was filed Thursday against the union.

The charge against the Sanders campaign also alleges, “At hiring, employer promised some employees housing, and not others; some were promised expenses, and others were not. The [collective bargaining agreement] requires relocation expenses be paid. Employer retaliated against me when I organized the bargaining unit and sent an email requesting compliance with the CBA.”

According to a copy of the collective bargaining agreement, state and field employees “may request supporter housing from the Employer, however the Employer is not required to provide housing and does not guarantee placement.”

The agreement also says, “If an Employee, at the request of the Employer, is required to relocate to a new office location that is at least fifty (50) miles further from the Employee’s home than the former job location was from their home, the Employer will provide a one-time, need-based relocation stipend of up to two thousand five hundred dollars.”