diff --git a/Koha/QueryParser/Driver/PQF/query_plan/node.pm b/Koha/QueryParser/Driver/PQF/query_plan/node.pm
index a50347e18c..353d7602d1 100644
--- a/Koha/QueryParser/Driver/PQF/query_plan/node.pm
+++ b/Koha/QueryParser/Driver/PQF/query_plan/node.pm
@@ -49,7 +49,7 @@ sub target_syntax {
         foreach my $field (@{$self->fields}) {
             $fieldobj = $self->plan->QueryParser->bib1_mapping_by_name('field', $self->classname, $field, $server);
             $relbump = $self->plan->QueryParser->bib1_mapping_by_name('relevance_bump', $self->classname, $field, $server);
-            if ($relbump) {
+            if ($relbump && defined $relbump->{'attr_string'}) {
                 $fieldobj->{'attr_string'} .= ' ' . $relbump->{'attr_string'};
             }
             push @fields, $fieldobj unless (!defined($fieldobj) || ($field eq $self->classname && @{$self->fields} > 1));
diff --git a/t/db_dependent/Search.t b/t/db_dependent/Search.t
index f66fc3e08f..608592b7e0 100644
--- a/t/db_dependent/Search.t
+++ b/t/db_dependent/Search.t
@@ -132,6 +132,10 @@ $contextmodule->mock('preference', sub {
         return 'holding';
     } elsif ($pref eq 'UNIMARCAuthorsFacetsSeparator') {
         return '--';
+    } elsif ($pref eq 'casAuthentication' or $pref eq 'casLogout' or $pref eq 'casServerUrl' ) {
+        return '';
+    } elsif ($pref eq 'template') {
+        return 'prog';
     } else {
         warn "The syspref $pref was requested but I don't know what to say; this indicates that the test requires updating"
             unless $pref =~ m/(XSLT|item|branch|holding|image)/i;