As a temporary workaround, in console and while the user is logged in, issue the commands: op <username> and if not someone you want as a operator then deop <username> and their xuid will be added to the permissions.json file.
Nathaniel Pettit
As a temporary workaround, in console and while the user is logged in, issue the commands: op <username> and if not someone you want as a operator then deop <username> and their xuid will be added to the permissions.json file.