A U.S. labour board official has concluded that Tesla (NASDAQ:TSLA) Inc supervisors at a Florida service centre broke the law by ordering workers not to bring complaints or discuss compensation with higher-level management.

According to the ruling made public on Tuesday by Administrative Law Judge Michael Rosas of the National Labour Relations Board (NLRB), managers at the Orlando repair company improperly silenced workers in 2021 after some of them raised concerns about new hires’ higher pay.

The judge commanded Tesla to stop infringing on the rights of employees, display notice of the infractions at the service centre, and email it to staff members.

The decision is the labour board’s latest setback for Tesla, which is now being sued over claims of pervasive racial and sexual discrimination at its assembly factories.

Tesla did not immediately respond to a request for comment.

The judgement states that workers learned that new hires at the collision centre were being paid a higher hourly rate than current employees in late 2021.

According to the decision, a number of employees complained, including a technician who spoke with a Tesla vice president and requested that his grievance be conveyed to the director of human resources at the business.

Rosas claimed that during a meeting at the service centre, supervisors instructed the 25 workers not to voice concerns about their salary or other working conditions or to approach more senior managers with their issues. Weeks later, the decision said that the technician who had complained had been let go.

The technician complained to the NLRB about Tesla last year, and Rosas held a hearing in February before reaching her decision on Tuesday.

According to Tesla’s defence, the company swiftly rejected the managers’ remarks by announcing in the service centre that it was okay for employees to discuss their salary.

Under American labour law, the judge ruled that attempts to intimidate workers infringed on their fundamental freedom to organise and demand better working conditions.

The judgement was rendered nearly a month after a U.S. appeals court upheld an NLRB finding that Tesla CEO Elon Musk had broken the law by tweeting that workers would lose stock options if they joined a union. The business is also contesting an NLRB ruling that said it had improperly prohibited production workers from donning union t-shirts.

The most valuable automaker in the world is also involved in numerous lawsuits alleging sexual harassment and racial discrimination, many of which centre on its main assembly facility in Fremont, California. In those situations, Tesla has denied wrongdoing.