Do you have an example you could point me towards? thanks in advance

I have lots of issues with old versions of workflows that don't show up in the list as shown above, but are still running under the name Deleted Association

We are having the same issue as ‌.  The workflow does not show in the Workflow Settings for the list but it remains in the Nintex Workflow Gallery and also shows in SharePoint Designer under "Workflows".  There are thousands of instances running for these "Deleted Association" workflows and no way to resolve them or stop them from happening.

After hours of support calls with Microsoft O365 support, they say Nintex will have to resolve or remove these workflows and Nintex says that Microsoft should resolve them.  NO HELP from either side!

I'd delete the list at that point. Copy off the content to another list and start over.