I believe it’s the same issue as ERROR cannot acquire lock file to read all the controllers: unable to open /tmp/juju-store-lock-3635383939333230: permission denied - #2 by wallyworld
Essentially at somepoint you ran with root.
You could try as root to clear the /tmp directory or ‘juju-*’ files and ensure you run the CLI as a non-root user to see if that solves the problem.