I've noticed in the Workflow Tasks list the Nintex tasks appear as 'Nintex Task Outcome [GUID string]' in the Content Type column. I assume there must be a place where this identifying name can be changed to reflect the form/workflow it's associated with, but I haven't found it. I need to be able to rename this to (for example) "Leave Request" or "AFE Form" to identify the Form/Workflow it is associated with.
Depending on customer preferences I did it on different ways:
For example naming the tasks with a a "prename" using the Form/Workflow Name some my tasks are named as: "AFE Form - ID5 - Approver1"
Or on other case I added a new column named "Form/Workflow" and then updated it on a parallel branch with the FlexiTasks, but it requires more work.
Once I tried to rename the Content Type that Nintex had auto-generated, I found out that approval stopped working. I guess there is some sort of co-relation between workflow assign tasks actions and its content type's names, including the GUID.. But haven't confirmed that with no-one from Nintex.
What I mean is.. you should not change the name of the Content Type. Have you tried to reach someone from Nintex?