When trying to confirm a task, the error message appears "User no longer have enough rights" and it is not possible to confirm the task.
Check all rights of the affected user and make sure that in a Custom Profile the option "Allow new entries" is also checked, as well as the "Search" right is given in Index Value Profiles.
If a new field is added and Custom Profiles / Index Value Profiles are used please make sure to check all relevant boxes for the new field as well.
If it is not possible to add the right(s) to one of the existing profiles, it is also possible to create a new profile and add the affected users here.