Run my code and see what it does.
Try this as an alternative:

foreach my $datapair (@data) {
   my ($label, $data) = split('=', $datapair);
######
   die "Bad Line: $datapair" if !defined ($data);
#####
   print "label: $label; data: $data\n";
   print OUT1 "$data;";
}
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