$history{ $+{ ticket } }{ $entry->{ action } } = {
   date => $words[0],
   time => $words[1],
   (\%+)->%{ grep exists( $+{ $_ } ), qw(
      order
      invoice
      shipment
      scheduled_date
      status
   ) }
};

##</code><code>##

sub kv { my $h = shift; $h->%{ grep exists( $h->{ $_ } ), @_ } }

kv( \%+, qw( ... ) )

##</code><code>##

$history{ $+{ ticket } }{ $entry->{ action } } = {
   date => $words[0],
   time => $words[1],
   (\%+)->%{qw(
      order
      invoice
      shipment
      scheduled_date
      status
   )}
};

##</code><code>##

$history{ $+{ ticket } }{ $entry->{ action } } = {
   date => $words[0],
   time => $words[1],
   %+,
};