src/de/steamwar/bungeecore/listeners/mods/Fabric.java

@@ -42,6 +42,8 @@ public class Fabric extends BasicListener {
 
     private final Set<String> neededMods = new HashSet<>();
 
+    public static List<ProxiedPlayer> checkedPlayers = new LinkedList<>();
+
     {
         neededMods.add("java");
         neededMods.add("minecraft");
@@ -61,6 +63,8 @@ public class Fabric extends BasicListener {
         ProxiedPlayer player = (ProxiedPlayer) e.getSender();
         SteamwarUser user = SteamwarUser.get(player.getUniqueId());
 
+        if(checkedPlayers.contains(player)) return;
+
         List<Mod> mods = new LinkedList<>();
 
         byte[] data = e.getData();
@@ -108,6 +112,7 @@ public class Fabric extends BasicListener {
         }
 
         if(Utils.handleMods(player,mods)) {
+            checkedPlayers.add(player);
             Storage.fabricPlayers.remove(player);
             Message.send("MODIFICATION_CHECK_SUCCESS", player);
         }

src/de/steamwar/bungeecore/listeners/mods/ModLoaderBlocker.java

@@ -58,6 +58,7 @@ public class ModLoaderBlocker extends BasicListener {
 
     @EventHandler
     public void onDisconnect(PlayerDisconnectEvent e){
+        Fabric.checkedPlayers.remove(e.getPlayer());
         Storage.fabricPlayers.remove(e.getPlayer());
     }