The Alphabet Workers Union has filed a complaint with the National Labor Relations Board (NLRB) against Google.

The complaint concerns a directive instructing employees not to discuss the company’s antitrust case.

This directive was issued by Google’s president of global affairs, Kent Walker, after a court ruling identified Google as holding an illegal monopoly.

The union argues that this instruction might prevent workers from engaging in protected discussions about workplace issues related to the case.

The NLRB’s investigation began on August 15 and will determine if labor rights were violated by assessing employee perceptions of the directive.

If the complaint is found valid, the matter could advance to an administrative law judge.