How are duplicated rows in tsv files handled?

[chahuistle]

I just tested uploading this file:

First Name      Last Name       Email   Title
One     Two     [email protected]       Mr.
One     Three   [email protected] Mr.
One     Two     [email protected]       Mr.

I got a message stating: "One Two contains a duplicate username or email already registered", which is "kind of correct", I think, because none of these users existed already.

I would've expected either the whole tsv file to be uploaded and all rows to be committed, but apparently rows are independently added.