Insted of
map { ... } split("\t", $line)
use
map { ... } $line =~ /(.*?)(?:\t|$)/g

>perl -le "@a = split(/\t/, """a\t"""); print scalar @a"
1

>perl -le "@a= """a\t""" =~ /(.*?)(?:\t|$)/g; print scalar @a"
2
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