I don't see anything obvious with your code. Try taking a few steps backwards, and just run the following code. It should create a file named 'foo.tmp' with just one line (bar). It also checks the success of print. Do you get any errors?

use strict;
use warnings;

my $list = 'foo';
my $newline = "bar\n";
open FH, '>', "$list.tmp" or die "$list == $!";
print FH $newline or die "Error print: $!";
close FH;
    
print $newline;
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