You are seeing HASH(0x28c0af8) because $entry is a reference to a hash. Notice the curly braces around the key-value pairs in your data structure:

               {
  
                 'name' => 'JOSPH',
                 'reference' => '0gft5210',

               }
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You'll want to deference that inner hash.

sub process {

    my $all = shift;
    my %run_all = %$all;

    foreach my $key (keys %run_all){
      print "$key\n";
      foreach my $entry (@{$run_all{$key}}) {
        while (my ($k, $v) = each %$entry) {
            print "$k => $v\n";
        }
       }
      print "\n";
     }
}
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