The Screen Actors Guild-American Federation of Television and Radio Artists called a strike against “League of Legends” on Tuesday, arguing that Formosa Interactive attempted to get around the ongoing video game strike by hiring non-union actors to work on an unrelated union title.

Formosa tried to “cancel” the unnamed video game, which was covered by the strike, shortly after the start of the work stoppage, SAG-AFTRA said. The union said when Formosa learned it could not cancel the game, the company “secretly transferred the game to a shell company and sent out casting notices for ‘non-union’ talent only.” In response, the union’s interactive negotiating committee voted unanimously to file an unfair labor practice charge against the company with the National Labor Relations Board and to call a strike against “League of Legends” as part of that charge.

“League of Legends” is one of Formosa’s most well-known projects. The company provides voiceover services for the game, according to SAG-AFTRA.

SAG-AFTRA has accused Formosa of interfering with protections that allow performers to form or join a union and prevent those performers from being discriminated against — a move the union called “egregious violations of core tenets of labor law.”

Formosa did not immediately respond to a request for comment. “League of Legends” developer Riot Games said that the company “has nothing to do” with the union’s complaint.

“We want to be clear: Since becoming a union project five years ago, ‘League of Legends’ has only asked Formosa to engage with union performers in the U.S. and has never once suggested doing otherwise,” Riot said in an emailed statement. “In addition, we’ve never asked Formosa to cancel a game that we’ve registered.”

SAG-AFTRA’s allegations are related to a non-Riot game, the game publisher said.

“It’s bad enough that Formosa and other companies are refusing to agree to the fair AI terms that have been agreed to by the film, television, streaming, and music industries, as well as more than 90 other game developers,” said the union’s national executive director, Duncan Crabtree-Ireland. “To commit illegal unfair labor practices is beyond the pale and won’t be tolerated by SAG-AFTRA members.”

SAG-AFTRA members must immediately stop providing covered services to “League of Legends,” the union said. Until Tuesday, the game was one of several titles that remained unstruck. Formosa is a union signatory.

“League of Legends is a game of champions. Instead of championing the union performers who bring their immense talent and experience to beloved characters, decision-makers at Formosa have chosen to try to evade and abandon them,” said Interactive Media Agreement Negotiating Committee Chair Sarah Elmaleh. “Such double-dealing is very disappointing from a longtime committed union signatory.”

SAG-AFTRA called a strike against major game companies in July after more than a year of negotiations around the union’s interactive media agreement broke down over concerns around the use of unregulated artificial intelligence. Formosa is a member of the bargaining group in those talks.