Tags imported via CSVImporter add-on aren't working

Loading tags via the Nuxeo CSV add-on are not working correctly.
e.g.

name,type,dc:title,nxtag:tags
MyFile,File,MyFile,"[{\"label\":\"Africa\",\"username\":\"Administrator\"}]"
MySecondFile,File,MySecondFile,"[{\"label\":\"Wet & Wild\"}]"

1. I can put whatever value I desire in username, regardless if whether there is such a user defined in the system (maybe not a bug).
2. if I leave username out altogether, I get null as a value, rather than myself. Expected: my username.
3. I am able to put values like This And That (mixed case with spaces) whereas when done via the UI these are always trimmed and set to lowercase.
4. the confirmation toast message in WebUI shows me a msg with the untrimmed mixed-case version as I typed it, despite that it's not what was saved to the document. Expected: at least tell me what the tag really was.
5. values created during CSV Import are not returned at all in the Tag suggestion (as I begin to type a letter, I don't see any of the existing tags that were imported via CSV, but only ones I added afterward via the UI)
6. I am unable to delete any tag created via CSV Importer. This was tested with username as null, with username of myself, and when the current user has ManageEverything permission.
7. Deleting a CSVImported tag erroneously shows me a 'confirmation toast' in the WebUI to tell me that the tag was successfully removed from the document, when in fact it was not. Expected: the truth is always better.