First of all thank you for creating Shopify!
There seems to be a bug on the Products page where when you create a new Tag, say “Featured” to an item and add when you go back to the listing without refreshing the entire page the “Featured” tag is not showing. You will have to refresh the entire page to see the new tag you created.
This caused me an issue because I mistakenly re-added the same tag “Featured” thinking I was not able to save it.
As a result, the tag named “Featured” now appeared two times in the tag list as:
Featured
Featured
and the URL now has to qualify which tag I meant causing it to name the second one as “featured-1” in the URL path.