$hash_ref=Clear($hash_ref); #Here something goes wrong.

Yup, this is why

#!/usr/bin/perl --
use strict; use warnings;
use Data::Dump;
my %hash = ( 1 .. 4 );
my $hashref = \%hash;
print "$hashref\n";
dd $hashref;
$hashref =~ s/^/WHY DID I DO THIS??? /;
dd $hashref;
__END__
HASH(0x99a99c)
{ 1 => 2, 3 => 4 }
"WHY DID I DO THIS??? HASH(0x99a99c)"
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