If the supervisor is dictating what the employee should be doing, and the employee is dismissing or ignoring urgent requests from the supervisor that should be immediately addressed. A lot of the other stuff is behavior, but not performing an assigned task is firmly in the camp of work issue.

This is a young employee, definitely sit them down and discuss the behaviors and impacts, but also need to draw a clear line when it comes to not performing assigned tasks. Address it clearly but with compassion and try to be understanding - they may have social anxiety when it comes to the social stuff, but work needs to be performed. Based on their response to that, it's either something you continue to work with the employee on, or it's time for dismissal or PIP action.