%200 success importing users?

I ran the importer on a site which had one user.
The import file had the same user name.

The results suggest I now have twice as many users ( completed 2/1, progress 200% ).

But I also received "error Failed to import user - username" twice.

I don't know from the error what the problem was. Is it really an error?
I assume it's because the same username has different email addresses.

This was copied from #33, where it was also reported that it imported users twice.

The issue names no files or tests. Start by reproducing the importer with one existing user and one imported user sharing a username, then inspect the reported count and error output; done means the duplicate-user behavior and the reason for any failure are clearly established.

Written by the indexing model from the issue text.