my $logged_events = []; should do the trick.

But it reads much nicer if you do it this way:

my @logged_events;
push @logged_events, $_ while $_ = $sth_le->fetchrow_hashref();

my $cordr_template = HTML::Template->new(filename=>$pdp_template,
                                            die_on_bad_params =>0,
                                           );
                                                    
$cordr_template->param(
                                   KPI           => $kpi,
                                   THRES       => $pdp_thres,
                                   DATETIME   => $currDateTime,
                                   NEW_EVENTS => $new_events,
                                   LOGGED_EVENTS => \@logged_events, )
+;
[download]

(modulo some code alignment you could also improve)