fix

ygopro-server.coffee

@@ -2902,7 +2902,7 @@ if settings.modules.mycard.enabled
 if settings.modules.heartbeat_detection.enabled
   setInterval ()->
     for room in ROOM_all when room and room.started and (room.hostinfo.time_limit == 0 or !room.turn or room.turn <= 0) and !room.windbot
-      for player in room.players when !room.changing_side or player.selected_preduel
+      for player in room.get_playing_player() when player and (!room.changing_side or player.selected_preduel)
         CLIENT_heartbeat_register(player, true)
     return
   , settings.modules.heartbeat_detection.interval

ygopro-server.js

@@ -3681,10 +3681,10 @@
       for (m = 0, len2 = ROOM_all.length; m < len2; m++) {
         room = ROOM_all[m];
         if (room && room.started && (room.hostinfo.time_limit === 0 || !room.turn || room.turn <= 0) && !room.windbot) {
-          ref2 = room.players;
+          ref2 = room.get_playing_player();
           for (n = 0, len3 = ref2.length; n < len3; n++) {
             player = ref2[n];
-            if (!room.changing_side || player.selected_preduel) {
+            if (player && (!room.changing_side || player.selected_preduel)) {
               CLIENT_heartbeat_register(player, true);
             }
           }