I have a problem with SharePoint and Nintex 2016, after the pause action, do not sent any task and notifications!
as soon as disable pause, i have received task and notification.
Can you try to add commit pending changes after pause action.
May be you can replace with commit pending changes as per your requrement.
login into the related Server where your SharePoint is, access to Services and try to restart the service "SharePoint Timer"
Try to run the workflow again after this operation.
The problem is not with the timer service ! Because after the pause, all actions are working correctly, just do not sent task and notification.
Here they had similar problem, actions run correctly also after Pause action but tasks/notifications don't: https://community.nintex.com/t5/Nintex-for-SharePoint/Send-notification-not-working/td-p/26200
It seems it is related to SharePoint Timer Job.