While I realize you can bulk upload tag’s and specify the tag group name as an optional parameter, please consider adding the bulk tag upload option when you are actually creating a tag group or even after the tag group has been created, via the manager. This would eliminate potentially uploading tags to an incorrect group name. In this scenario, it would obviously eliminate the need to encode the csv file to include the optional tag group name and make that parameter truly optional.
It would also be a nice feature, when deleting a tag group name, there was an option to delete all tags associated with said group name.
I originally thought it was a bug when I was experimenting uploading two different tags with he same group name, via bulk upload. Unknown to me I had a space after one of the tag group names and when I uploaded the file. It appeared there was a bug because I had two different tag groups with the same name.
Perhaps, you can check for and truncate spaces after the tag group name when uploading via CSV.