How was the second instance allowed to be tagged?
I expected the duplicate tag to be automatically cleared/dissolved when
Lance saved the edit.
Removed the duplicate tag (see the revisions link).
But, is this expected behavior?
If it is allowed to repeat a tag -- why?
random says, a global conversion caused the duplication of this tag,
I'd still kind-of expect the conversion to be implemented to check for such duplicates
(caused by it).
I would also be surprised to find someone choose to shorten a tag and
did not delete the older longer form (for the conversion to cause a duplicate later).