Users are not able to update iteration for defects, they are getting a strange error as below:
Release : 1.0
Component : API FOR AGILE CENTRAL
These issues are caused due to workspace moves.
Please go to the task collection on the defects and update the owner to a user that is on the existing team and save it --> it will help the workitem to update iterations values.
These issues occur when the user that owned the tasks didn’t move with the data, So the owner field is showing a - instead of No entry or blank.