lib/PublicInbox/LeiXSearch.pm | 6 +++---
 t/lei-q-thread.t              | 8 ++++++--

diff --git a/lib/PublicInbox/LeiXSearch.pm b/lib/PublicInbox/LeiXSearch.pm
index 3270b420b64c18a94b74b67574c8e5089b91de0f..f2c8c02e8c653c7d670128093a31d0d4c7049c93 100644
--- a/lib/PublicInbox/LeiXSearch.pm
+++ b/lib/PublicInbox/LeiXSearch.pm
@@ -148,7 +148,7 @@ 	my $mo = { %{$lei->{mset_opt}} };
 	my $mset;
 	my $each_smsg = $lei->{ovv}->ovv_each_smsg_cb($lei, $ibxish);
 	my $can_kw = !!$ibxish->can('msg_keywords');
-	my $fl = $lei->{opt}->{threads} > 1;
+	my $fl = $lei->{opt}->{threads} > 1 ? [ 'flagged' ] : undef;
 	do {
 		$mset = $srch->mset($mo->{qstr}, $mo);
 		mset_progress($lei, $desc, $mset->size,
@@ -165,8 +165,8 @@ 				my $mitem = delete $n2item{$smsg->{num}};
 				if ($mitem) {
 					if ($can_kw) {
 						mitem_kw($smsg, $mitem, $fl);
-					} else {
-						$smsg->{kw} = [ 'flagged' ];
+					} elsif ($fl) {
+						$smsg->{kw} = $fl;
 					}
 				}
 				$each_smsg->($smsg, $mitem);
diff --git a/t/lei-q-thread.t b/t/lei-q-thread.t
index 0ddf47a69fe12741a1b1ef320e63a567ea45394e..28c639f5e35c22e0cfba0ac3dbe16b779001ea0a 100644
--- a/t/lei-q-thread.t
+++ b/t/lei-q-thread.t
@@ -41,8 +41,12 @@ 	is_deeply($m{'<testmessage@example.com>'}->{kw}, ['flagged', 'seen'],
 		'flagged set in direct hit');
 	'TODO' or is_deeply($m{'<testmessage@example.com>'}->{kw}, ['draft'],
 		'flagged set in direct hit');
-	lei_ok qw(q -t -t m:testmessage@example.com --only), "$ro_home/t2";
+	lei_ok qw(q -tt m:testmessage@example.com --only), "$ro_home/t2";
 	$res = json_utf8->decode($lei_out);
-	is_deeply($res->[0]->{kw}, [ 'flagged' ], 'flagged set on external');
+	is_deeply($res->[0]->{kw}, [ 'flagged' ],
+		'flagged set on external with -tt');
+	lei_ok qw(q -t m:testmessage@example.com --only), "$ro_home/t2";
+	$res = json_utf8->decode($lei_out);
+	ok(!exists($res->[0]->{kw}), 'flagged not set on external with 1 -t');
 });
 done_testing;