For SharePoint 2013 are Nintex tasks aggregated by the Work Management Service? We have WMS turned on in our environment and its working on aggregating all the tasks but the Nintex Review and Approval tasks from all site.
Is this a bug or is this a feature request?
No -- Nintex workflow tasks are aggregated through a table in the Nintex content database. WMS is not utilized by the Nintex Workflow process. You are welcome to submit a feature request at http://nintex.uservoice.com