We are using a flexi task to assign individual task to a group of users and we also have enabled auto complete in the escalation tab.
OutComes: only 1 outcome
Behaviour: First response applies
So when none of the user complete the task, the workflow auto completes the 1st task and then it errors out.
Have you tested on another list if same issue occurs? ITry creating new task form by deleting it else Try the solution from SharePoint: “Response no longer required” error in nintex workflow which may be helpful
I am not sure if i understand your issue in right direction. But think about following points.
1. As you said only 1 outcome. I don't think in Assign Flexi task you can put only one outcome as by default it needs min 2 outcomes.
2. In escalation tab please check the time to escalation.
3. When you put auto complete in escalation tab after certain time, i think you should make sure you give the Outcome field value in Integer format, instead of giving it accept or reject text format. You can find integer value of the outcomes by opening Edit Form and right clicking & selecting properties of outcome radio buttons. by default they should be 0 & 1. but it differs sometimes.
I am having same issue. Has anyone found the solution yet. We have task assigned to three users but auto complete the task with Outcome ESCALATION after certain time? The workflow simply errors out.