I tried Text::CSV_XS again and had zero problems. All I can figure is that maybe somewhere along the line it had something to do with seemingly escaped metacharacters. So things like "\\\t" (slash followed by a tab) might have confused it. I do recall that at the time, identical input was in some cases handled by Text::CSV and not handled by Text::CSV_XS though I can't seem to find what the failure mode is just now.