For a start it doesn't use strictures (use strict; use warnings).

You may find changing

    @$spr_hash{$file_name} = <FH>;
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to

    @{$spr_hash{$file_name}} = <FH>;
[download]

helps. The following sample script would have shown the problem more clearly:

use strict;
use warnings;
use Data::Dumper;

my $file_name = 'test.txt';
my %spr_hash;

$spr_hash{$file_name} = [];
@$spr_hash{$file_name} = qw(1 2 3);

print Dumper [ %spr_hash ];
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