Issue
After upgrading to Nintex Workflow 2013 3.2.2.0, workflows are getting stuck on the Send Notification.
Resolution
Update to Nintex Workflow for SharePoint 2013 3.2.2.10 or newer version.
Additional Information
This issue was caused by a defect introduced in 3.2.2.0 and has been resolved in 3.2.2.10.