Thomson Reuters’s legal issues aren’t limited to the FindLaw suit we mentioned earlier today. The company is also under fire from the National Labor Relations Board, which will file a civil complaint in defense of a Reuters reporter who commented on union negotiations via Twitter.

Thomson Reuters reprimanded Deborah Zabarenko after she tweeted, “One way to make this the best place to work is to deal honestly with Guild members,” reports The New York Times. Zabarenko covers the environment for Reuters and also leads its Newspaper Guild.

The NLRB says the reprimand amounted to a violation of Zabarenko’s right to discuss working conditions. Its case would be the first brought by the government against an employer that involves Twitter. “Labor law specialists say employees have the right to criticize or disparage their companies or supervisors as part of a conversation aimed at improving working conditions, but do not have the right to merely curse supervisors or make untrue, disloyal statements that damage a company’s reputation,” the Times reports.

Romenesko has posted a New York Guild press release about the complaint.