The approve/reject view IS an edit form of a task list item! It's the edit form of the task item you created via your workflow.
Can you please provide a screenshot to clearify your problem?
Hello Philipp,
I got this issue resolved, I have used the nwadmin SetTaskForm operation to fix the connection problem between taskform and the content type.
I have run the following command in SharePoint management shell in the web front end server.
NWAdmin.exe -o SetTaskForm -siteUrl "your site/site collection" -contentType "Nintex Workflow Task" -taskformUrl "_layouts/nintexworkflow/ApproveReject.aspx" -updatechildren Yes
Thank you.
I have to admit that I still don't really understand what the problem was (maybe because it's friday )
But I'm very happy to hear you got it working again!
Have a nice weekend
Philipp