I have never seen anything remotely like this before.
SharePoint 2016 - Nintex Workflows
In every Library/List, except one (started this morning), I can click on an item and select Workflows (either from Drilldown menus, or Ribbon). The one this morning is giving me an error whenever I try to get to Workflows (the famous “Sorry something went wrong, an unexpected error has occurred”). It gives me a Correlation ID, but I find nothing for that in the ULS logs.
I have even gone as far as removing Nintex feature from site and re-adding it.
Any ideas?