Edit on the previous comments, the processes are not owned by the user, processes are owned by root but ps returns several lines like:
/usr/lib/policykit-1/polkit-agent-helper-1 USERNAME
where USERNAME is the user that gets stuck
Edit on the previous comments, the processes are not owned by the user, processes are owned by root but ps returns several lines like:
/usr/lib/ policykit- 1/polkit- agent-helper- 1 USERNAME
where USERNAME is the user that gets stuck