When I tried to delete a workflow there was an error...

At first I noticed there were a few orphaned workflow instances and after cleaning those items up I tried to delete the workflow again.

The same message appears...

Upon some more investigation using SharePoint Designer I noticed the workflow is actually not in the the site. It appears it was actually delete but, still appearing in the list of active workflows. Also, I when I run the Finding all of the workflows in your farm using PowerShell​ I noticed the workflow appears 2 times. So my questions:

1. How do I permanently delete the workflow record?

2. Why does it show 2 records for the same workflow? It has duplicated records for some workflows.

Thanks in advance for your advice!