One of the mistakes that product managers are likely to make is that they are nowhere to be found once the project is started. Sometimes product managers just explain the stories on the sprint planning meeting, and then nothing else. This will cause problems.

• First of all, team members cannot understand all about the stories just by attending planning meetings. Therefore, all the team members should check the status of the projects all the time, and solve the problems once found.
  
• Second, it might cause antagonism between product managers and development teams, if product managers are not involved in the project. It is detrimental to the team. Besides, product managers and development teams would pass bucks to each other.

Therefore, product managers should follow up the projects by attending daily scrum meetings, tracking task progresses through the Project module in ZenTao, and check bug status, confirm stories done on time. 

Once the project is completed, the stories in the current sprint should be confirmed so to make sure it is what they want. Meanwhile, a retrospective meeting should be held to gather opinions and feedback from others. Later they should organize the opinions and feedbacks into stories and then import them into ZenTao.