Is that a v3 issue, or just an oddity you're seeing now on v2.x?
Check the running instances to see which user is running ps aux | grep node
Both loader.js and app.js should be running under the same user.
@killerham said in Error When trying to change the username for a user as an admin:
user's username as an admin, getting
What version of NodeBB? I think this was fixed in the latest version.