I have created a custom workflow in SharePoint Designer where I want users to have the ability to approve anothers task if need be. I use a "Custom Task Process" to assign the task to the user.
When a user with higher permission levels, in this case "Full Control" permissions, trys to approve the task for the individual they are prompted with a SharePoint error message that they cannot approve tasks which are assigned to another individual.
What preplexes me is I have a similiar workflow, in which I use the "Custom Task Process" and users with Approver or Full Control permissions can approve another individuals tasks.