Discord Bug Bans 8,200 Users for Posting Grid Images

A bug in Discord's content moderation system has resulted in approximately 8,200 users being incorrectly banned since May for posting inoffensive images containing grids, such as chessboards, game textures, and video game inventory screenshots. The Verge reported that around 8,000 users were banned during this period, with an additional 200 banned over a recent weekend. Discord acknowledged the issue on X, stating that all affected accounts have been reinstated. The company explained that its safety systems use perceptual hashing to match images against known harmful material, but a bug prevented cleared accounts from being unbanned correctly. Discord said it is working on safeguards to prevent such "quiet" bans in the future. Perceptual hashing, as described by UK regulator Ofcom, converts images to grayscale, downsizes them, divides them into a grid, and assigns brightness values to create unique identifiers. This technology is used by Microsoft's PhotoDNA to combat CSAM and by platforms like Dropbox for copyright detection. The incident highlights the limitations of automated content moderation systems.