If you know the pseudo-hashes are empty of data then a simple check and skip might suffice

foreach my $type (@type_order) {
  print "$log_pre running $action for $type entries\n"; 
  # Iterate over all items of that type 
  my $type_hash = $hashref->{$type}; 
  next unless ref($type_hash) eq 'HASH'; # <-- add
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If you are not sure then use

foreach my $type (@type_order) {
  # Iterate over all items of that type 
  my $type_hash = $hashref->{$type}; 

  if ( (ref($type_hash) eq 'ARRAY') && (@$type_hash<2) ){
    print "Skipping empty pseudo-hash for $type entries\n";
    next;
  } else {
    print "$log_pre running $action for $type entries\n"; 
  }
  .
  .
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