Tasks’ permissions in Nintex Workflow for Office 365

In Nintex Workflow for SharePoint (every version), when you use the “Flexi task” action, that creates and assigns tasks to specific users, if you (as a viewer) are not the assignee, workflow tells you that “You are not authorized to respond to this task.” – then to make yourself authorized you have to click the “delegate” link, then to reassign that task to yourself.