The example raw CSV given did not work as an import, and according to the documentation of the function that raised the error, ParseAdress, the verification of the validity of mails is done according to RFC 5322, which specifies that the local part of the mail (before the @) cannot contain spaces if it is not quoted
In section 3.4.1:

The locally
interpreted string is either a quoted-string or a dot-atom. If the
string can be represented as a dot-atom (that is, it contains no
characters other than atext characters or "." surrounded by atext
characters), then the dot-atom form SHOULD be used and the quoted-
string form SHOULD NOT be used.

And the format of atext is defined in section 3.2.3) as follows :

atext           =   ALPHA / DIGIT /    ; Printable US-ASCII
                       "!" / "#" /        ;  characters not including
                       "$" / "%" /        ;  specials.  Used for atoms.
                       "&" / "'" /
                       "*" / "+" /
                       "-" / "/" /
                       "=" / "?" /
                       "^" / "_" /
                       "`" / "{" /
                       "|" / "}" /
                       "~"