Generally chop should be avoided and chomp used instead.

ord is a better way to "see" strange characters:

open(FH,'orders.csv') or die "$!";
while($line = <FH>) {
  my $character = chop($line);
  print ord ($character), "\n";
}
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Most likely you have fallen foul of network / local OS line end differences or code that doesn't appreciate such differences. The new line character is being treated as a line end character where really there is a cr/lf pair and the cr (carriage return) is being passed back as the last character on the line.