One item created - get notifcation mail many times

I'm using Nintex Workflow 2013, Version: 3.2.4.0 - English. I have the issue, that I get the notification mail, that an item has been created many times. The workflow is based on a user defined site content type.  I have the same issue in every list, that I created using this user defined site content type. At the beginning I didn't have the problem. 

Workflow history:

Workflow Status

Do you have an idea for the issue?

Thank you!

Christian