Index: template.php
--- template.php
+++ template.php
@@ -3320,6 +3320,11 @@
 			$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 );
 
+		// Topic has no voices (likely created by an anonymous user)
+		} elseif ( empty( $vc_int ) && ! empty( $last_active ) ) {
+			$last_updated_by = bbp_get_author_link( array( 'post_id' => $last_active, 'size' => $r['size'] ) );
+			$retstr          = sprintf( esc_html__( 'This topic was last updated %3$s by %4$s.', 'bbpress' ), $reply_count, $voice_count, $time_since, $last_updated_by );
+
 		// Topic has no replies
 		} elseif ( ! empty( $vc_int ) && ! empty( $reply_count ) ) {
 			$retstr = sprintf( esc_html__( 'This topic has %1$s and %2$s.', 'bbpress' ), $voice_count, $reply_count );