Grand Theft Auto V was one of the top ten most played games on Valve’s Steam Deck handheld this past week. It’s been in the top twenty for at least two years. But as of today, Valve now lists the game as “unsupported” — because developer Rockstar mysteriously broke compatibility with Valve’s handheld for its online modes.

As you can see in the image above, this is the latest fight around Linux anti-cheat: like the developers of Fortnite and Roblox, Rockstar has decided not to support the Steam Deck with its new anti-cheat software for GTA Online — a game that, by all accounts, badly needed to deal with cheaters. (Outside the Steam Deck, better anti-cheat was probably a good move.)

But unlike Fortnite and Roblox, Rockstar is taking the multiplayer chunk of the game away from people, rather than not bringing it to the Steam Deck in the first place. It’s also blaming Valve for the problem, claiming that “Steam Deck does not support BattlEye for GTA Online” and directing all further questions to Valve.

And it’s not answering one key question: why didn’t it flip the alleged switch that lets BattlEye anti-cheat work on the Steam Deck?

Because it does work, last I checked. Valve enabled BattlEye for the Steam Deck years ago, and a number of games with the anti-cheat software successfully made the jump. Valve has said that enabling a game with BattlEye to run on Steam Deck is literally as easy as sending an email. But Rockstar didn’t reply when I asked about that. I also pinged Valve’s Pierre-Loup Griffais to see if anything has changed in the anticheat scene since, but haven’t yet heard back.

I have repeatedly heard it suggested that letting Linux users play around with anti-cheat invites them to figure out ways to dismantle it, but Epic’s Tim Sweeney suggested last year that it might be more about economics.

On the plus side, GTA V’s single player should still work. “You will be able to play GTAV Story Mode but unable to play GTA Online,” reads Rockstar’s FAQ.