diff --git a/src/wp-includes/comment.php b/src/wp-includes/comment.php
index 20303dc1e7e17..e421f5415dce3 100644
--- a/src/wp-includes/comment.php
+++ b/src/wp-includes/comment.php
@@ -363,15 +363,15 @@ function get_lastcommentmodified( $timezone = 'server' ) {
 
 	switch ( $timezone ) {
 		case 'gmt':
-			$comment_modified_date = $wpdb->get_var( "SELECT comment_date_gmt FROM $wpdb->comments WHERE comment_approved = '1' ORDER BY comment_date_gmt DESC LIMIT 1" );
+			$comment_modified_date = $wpdb->get_var( "SELECT comment_date_gmt FROM $wpdb->comments WHERE comment_approved = '1' AND comment_type != 'note' ORDER BY comment_date_gmt DESC LIMIT 1" );
 			break;
 		case 'blog':
-			$comment_modified_date = $wpdb->get_var( "SELECT comment_date FROM $wpdb->comments WHERE comment_approved = '1' ORDER BY comment_date_gmt DESC LIMIT 1" );
+			$comment_modified_date = $wpdb->get_var( "SELECT comment_date FROM $wpdb->comments WHERE comment_approved = '1' AND comment_type != 'note' ORDER BY comment_date_gmt DESC LIMIT 1" );
 			break;
 		case 'server':
 			$add_seconds_server = gmdate( 'Z' );
 
-			$comment_modified_date = $wpdb->get_var( $wpdb->prepare( "SELECT DATE_ADD(comment_date_gmt, INTERVAL %s SECOND) FROM $wpdb->comments WHERE comment_approved = '1' ORDER BY comment_date_gmt DESC LIMIT 1", $add_seconds_server ) );
+			$comment_modified_date = $wpdb->get_var( $wpdb->prepare( "SELECT DATE_ADD(comment_date_gmt, INTERVAL %s SECOND) FROM $wpdb->comments WHERE comment_approved = '1' AND comment_type != 'note' ORDER BY comment_date_gmt DESC LIMIT 1", $add_seconds_server ) );
 			break;
 	}
 
diff --git a/tests/phpunit/tests/comment/getLastCommentModified.php b/tests/phpunit/tests/comment/getLastCommentModified.php
index 03229ba350a9b..9f8f9e08857fb 100644
--- a/tests/phpunit/tests/comment/getLastCommentModified.php
+++ b/tests/phpunit/tests/comment/getLastCommentModified.php
@@ -11,6 +11,37 @@ public function test_no_comments() {
 		$this->assertFalse( get_lastcommentmodified() );
 	}
 
+	/**
+	 * Ensures internal 'note' comments are excluded from the last modified time.
+	 *
+	 * The value feeds the comments feed Last-Modified/ETag headers, so a note --
+	 * which is never part of the public feed -- must not bump it.
+	 *
+	 * @ticket 65657
+	 */
+	public function test_notes_are_excluded() {
+		// A regular approved comment.
+		self::factory()->comment->create(
+			array(
+				'comment_approved' => '1',
+				'comment_date'     => '2000-01-01 11:00:00',
+				'comment_date_gmt' => '2000-01-01 10:00:00',
+			)
+		);
+
+		// A later internal note, which must be ignored.
+		self::factory()->comment->create(
+			array(
+				'comment_approved' => '1',
+				'comment_type'     => 'note',
+				'comment_date'     => '2000-01-02 11:00:00',
+				'comment_date_gmt' => '2000-01-02 10:00:00',
+			)
+		);
+
+		$this->assertSame( strtotime( '2000-01-01 10:00:00' ), strtotime( get_lastcommentmodified( 'GMT' ) ) );
+	}
+
 	public function test_default_timezone() {
 		self::factory()->comment->create_and_get(
 			array(