before 1.18.2 version, minecraft server(download page link here) won't kick player if "online-mode" is set to "false" in server file "server.properties", even player use unicodes in their name(chinese, korean, japanese words). now players with unicodes in names will get kiced with message "Internal Exception: java.lang.IllegalStateException: Invalid characters in username" even when "online-mode" has been set to "false". this issue appeared since version 1.18.2. this also resulted in some special minecraft versions (such as NetEase's China Edition) stuck forever before version 1.18.2.

instead of forcing players to use "legitimate" usernames from the source, please leave the checking authority of nicknames to third-party server software(spigot, paper, bungee). this will prevent players from tens of thousands of servers from playing the latest version.

This is definitely an issue that hopes to be fixed, it's not a suggestion, because it has violated the previous program logic, "online-mode" itself is used to ignore crack detection, and now this function is invalid, and this should be hopefully fixed.