I cannot see a problem here.
This was tested with a default TAdvListView on the form initialized with:
procedure TForm5.Button1Click(Sender: TObject);
begin
advlistview1.Testfill;
advlistview1.ClipboardEnable := true;
advlistview1.MultiSelect := true;
advlistview1.RowSelect := true;
end;
When selecting all rows and copy to the clipboard, this is pasted as:
0 s1 s2
1 s1 s2
2 s1 s2
3 s1 s2
4 s1 s2
5 s1 s2
6 s1 s2
7 s1 s2
8 s1 s2
9 s1 s2