Fixed a client error when it tries to add the same achievement to a profile twice

project/SPT.SinglePlayer/Patches/RaidFix/FixKeyAlreadyExistsErrorOnAchievementPatch.cs

@@ -0,0 +1,26 @@
+using System.Reflection;
+using HarmonyLib;
+using SPT.Reflection.Patching;
+
+namespace SPT.SinglePlayer.Patches.RaidFix
+{
+    public class FixKeyAlreadyExistsErrorOnAchievementPatch: ModulePatch
+    {
+        protected override MethodBase GetTargetMethod()
+        {
+            return AccessTools.Method(typeof(AbstractAchievementControllerClass), nameof(AbstractAchievementControllerClass.OnConditionalStatusChangedEvent));
+        }
+
+        [PatchPrefix]
+        public static bool Prefix(GClass1368 achievement, bool notify, AbstractAchievementControllerClass __instance)
+        {
+            if (achievement.IsDone() && __instance.Profile.AchievementsData.ContainsKey(achievement.Id))
+            {
+                // Tries to add same achievement key a second time, throwing a "An item with the same key has already been added" error
+                return false; // Skip original
+            }
+
+            return true; // Do original
+        }
+    }
+}

project/SPT.SinglePlayer/SPTSingleplayerPlugin.cs

@@ -63,6 +63,8 @@ namespace SPT.SinglePlayer
 				new ScavIsPlayerEnemyPatch().Enable();
 				new BotOwnerManualUpdatePatch().Enable();
 				new FirearmControllerShowIncompatibleNotificationClass().Enable();
+                new FixKeyAlreadyExistsErrorOnAchievementPatch().Enable();
+
             }
             catch (Exception ex)
             {