If Playlist Ticket Assignment is not assigning tickets as expected, it is most likely due to how your conditions are set up in your views.
In order to avoid hitting Zendesk's API limits, the app only checks for the 10 oldest tickets in each view. Therefore, Playlist requires that views used in Playlist rules filter for only unassigned tickets. This ensures that no unassigned tickets are missed.
Under "Meet all of the following conditions", there should be the condition: Ticket: Assignee Is -. Add the condition to your view if it's not already there.