Fortnite

"Fortnite's signatory company, Llama Productions, chose to replace the work of human performers with A.I. technology," the statement added. "Unfortunately, they did so without providing any notice of their intent to do this and without bargaining with us over appropriate terms. As such, we have filed an unfair labor practice charge with the NLRB against Llama Productions."

The filing itself says: "Within the past six months, [Epic Games], by its agents and representatives, failed and refused to bargain in good faith with the union by making unilateral changes to terms and conditions of employment, without providing notice to the union or the opportunity to bargain, by utilizing AI-generated voices to replace bargaining unit work on the Interactive Program Fortnite."

It sounds like they're unhappy with the behaviour of the studio Epic contracted the work to. I think.