Exchange Create Task action does not update SharePoint list item

Hello,

I am using a SharePoint task list and have a Nintex Workflow action create a new Exchange Task to the person assigned so they can see this as a task in Outlook or on their phones. While I can create the task, and the user can complete the task, the originating item in SharePoint is never updated. Could someone please help me understand how to make this round-trip update possible?

The client is on SharePoint 2013, Nintex Workflow 2013, Exchange 2010. Unfortunately, tasks created in SharePoint 2013 will only show up as tasks when using Exchange 2013, which is why I need Nintex to do this for me.

Thanks. -Bill