fix dupe glitch with backpacks (#4134)

src/main/java/io/github/thebusybiscuit/slimefun4/api/player/PlayerProfile.java

@@ -394,12 +394,18 @@ public static boolean get(@Nonnull OfflinePlayer p, @Nonnull Consumer<PlayerProf
         loading.put(uuid, true);
         Slimefun.getThreadService().newThread(Slimefun.instance(), "PlayerProfile#get(" + uuid + ")", () -> {
             PlayerData data = Slimefun.getPlayerStorage().loadPlayerData(p.getUniqueId());
-            loading.remove(uuid);
 
             AsyncProfileLoadEvent event = new AsyncProfileLoadEvent(new PlayerProfile(p, data));
             Bukkit.getPluginManager().callEvent(event);
 
             Slimefun.getRegistry().getPlayerProfiles().put(uuid, event.getProfile());
+
+            // Make sure we call this after we put the PlayerProfile into the registry.
+            // Otherwise, we end up with a race condition where the profile is not in the map just _yet_
+            // but the loading flag is gone and we can end up loading it a second time (and thus can dupe items)
+            // Fixes https://github.com/Slimefun/Slimefun4/issues/4130
+            loading.remove(uuid);
+
             callback.accept(event.getProfile());
         });
 
@@ -434,10 +440,15 @@ public static boolean request(@Nonnull OfflinePlayer p) {
             // Should probably prevent multiple requests for the same profile in the future
             Slimefun.getThreadService().newThread(Slimefun.instance(), "PlayerProfile#request(" + uuid + ")", () -> {
                 PlayerData data = Slimefun.getPlayerStorage().loadPlayerData(uuid);
-                loading.remove(uuid);
 
                 PlayerProfile pp = new PlayerProfile(p, data);
                 Slimefun.getRegistry().getPlayerProfiles().put(uuid, pp);
+
+                // Make sure we call this after we put the PlayerProfile into the registry.
+                // Otherwise, we end up with a race condition where the profile is not in the map just _yet_
+                // but the loading flag is gone and we can end up loading it a second time (and thus can dupe items)
+                // Fixes https://github.com/Slimefun/Slimefun4/issues/4130
+                loading.remove(uuid);
             });
 
             return false;