Repeatable Regions

[Angryboy]

You can if you really want to keep your meta data clean but it is honestly harmless. Tags with the _ can be searched for but are never actually displayed on the pages themselves. I'd personally just leave it be.

If you seriously want itthough, just make sure that you make your new special field index-enabled for tags (you'll see a dropdown box with the option for this on the page that you're defining the fields).