Most likely, your $var1 and/or $var2 are not clean. Somewhere there is(are) returns.

This helps to visually inspect your strings: (just pass your $var1, $var2 as parameters)

use strict;
use warnings;

inspect("abcd\n123");

sub inspect {
    (my $copy = shift) =~ s/([^[:print:]])/sprintf " (0x%02x) ", ord $
+1/ge;
    print $copy;
}
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If your $var1 and $var2 are read from terminal or a file, you might want to chomp them.