Index: includes/topics/template.php
===================================================================
--- includes/topics/template.php	(revision 3242418)
+++ includes/topics/template.php	(working copy)
@@ -3319,7 +3319,8 @@
 		$last_active = bbp_get_topic_last_active_id( $topic_id );
 		if ( ! empty( $vc_int ) && ! empty( $last_active ) ) {
 			$last_updated_by = bbp_get_author_link( array( 'post_id' => $last_active, 'size' => $r['size'] ) );
-			$retstr          = sprintf( esc_html__( 'This topic has %1$s, %2$s, and was last updated %3$s by %4$s.', 'bbpress' ), $reply_count, $voice_count, $time_since, $last_updated_by );
+			/* translators: %1$s - reply count, %2$s - voice count voices, %3$s - time since, %4$s - last updated by */
+			$retstr = sprintf( esc_html ( _n( 'This topic has %1$s, %2$s, and was last updated %3$s by %4$s.', 'This topic has %1$s, %2$s, and was last updated %3$s by %4$s.', $reply_count, 'bbpress') ), $reply_count, $voice_count, $time_since, $last_updated_by );
 
 		// Topic has no replies
 		} elseif ( ! empty( $vc_int ) && ! empty( $reply_count ) ) {