I have found that when I am adding a tag to a task, it allows you to create duplicate tags. For instance, I have a tag graphic design. There are multiple other tags that include either “graphic” or “design.” So many that you have to scroll up on the dropdown tag list, as it’s not readily visible. We can discuss the merits of getting really specific about tag naming so that it drills down further, but I have multiple users who add tags to tasks, and do not take the time to scroll up, so when they see the “new tag” option after they’ve typed “graphic design,” they click on that and create a new, duplicate graphic design tag. This gets really frustrating for me when I am attempting to report on graphic design requests for a month. When I search, I see two or more graphic design tags and then have to add the original tag to the tasks with the duplicate tag and then delete the duplicate tag. Is there a way to prevent users from creating duplicate tags? Asana will create a duplicate tag with the same phrase even if one phrase has the first letter capitalized and the user types it all lowercase.
Absolutely agree. Sometimes the tag list loads a bit slow and it is pretty easy to create duplicates by mistake.
And - as KellyB writes correctly - removing a duplicate is somewhat painful.
I work a lot with favorite searches and it would be no fun to miss an “important” task in this view just because the major work item for the week was tagged with the wrong “important” by mistake.
This is a very annoying issue. Why is it even still possible?
Who would even need separate tags with the same names 
Also noticing this issue, seems like the local tags list is not kept up-to-date when a tag gets created+added to a task. Workaround seems like to do an app refresh when creating a new tag, but ideally the local tag cache is updated when the new tag is created.
A related issue I just noticed. When a tag gets deleted, saved searches still work as if that tag were still active (i.e., they still find the tasks that once-upon-a-time had that tag). However the search won’t locate a re-created tag with the same name.