League of Legends is facing a backlash after players discovered its online chat system censored the term "Uighur".
Uighurs are a Muslim ethnic minority who claim they have faced human rights abuses from the Chinese government.
Developer Riot Games acknowledged the fault, and blamed its filtering system for "banning words it shouldn't".
However, player complaints on official forums were blocked, and it is alleged a variety of other sensitive words like "freedom" are also being censored.
Users initially raised the issue on League of Legends' official forums, but due to rules stating that discussions about "ethnicity and race" are banned, their complaints were ignored.
Frustrated gamers then voiced their concerns on Reddit, which led Ryan Rigney, communications lead at Riot Games, to address the controversy in a series of Tweets:
"Just saw a thread on Reddit about our text-filtering system banning words it shouldn't. It would be ridiculous and absurd to hide the name of any ethnic group," he wrote.
Mr Rigney added that the company has fixed the issue, and will be spending "the next few weeks" reviewing and updating its banned words and phrases list.
The BBC has contacted developer Riot Games and publisher Tencent for comment.
Uighurs are mostly based in China's Xinjiang province, where they make up around 45% of the population. Xinjiang is officially designated as an autonomous region within China, like Tibet to its south.
Human rights groups, including Amnesty International and Human Rights Watch, submitted reports to the UN Committee on the Elimination of Racial Discrimination this year, documenting claims of mass imprisonment in camps, where inmates are forced to swear loyalty to China's President Xi Jinping.
The World Uighur Congress said in a recent report that detainees are held indefinitely without charge, and forced to shout Communist Party slogans.
It's the latest in a series of complaints from League of Legends users this year, after players in Iran reported being blocked from playing the game due to US sanctions against the country.
Gamers shared their experiences in League of Legends' online forums, pleading with the US government to rethink extending its trade sanctions to gamers.