diff --git a/Source/Game/Achievements/CriteriaHandler.cs b/Source/Game/Achievements/CriteriaHandler.cs
index 31b4b69bf..75c13d20a 100644
--- a/Source/Game/Achievements/CriteriaHandler.cs
+++ b/Source/Game/Achievements/CriteriaHandler.cs
@@ -1848,10 +1848,8 @@ namespace Game.Achievements
                     break;
                 }
                 case ModifierTreeType.PlayerHasCompletedQuest: // 110
-                    uint questBit = Global.DB2Mgr.GetQuestUniqueBitFlag(reqValue);
-                    if (questBit != 0)
-                        if ((referencePlayer.m_activePlayerData.QuestCompleted[((int)questBit - 1) >> 6] & (1ul << (((int)questBit - 1) & 63))) == 0)
-                            return false;
+                    if (!referencePlayer.IsQuestCompletedBitSet(reqValue))
+                        return false;
                     break;
                 case ModifierTreeType.PlayerIsReadyToTurnInQuest: // 111
                     if (referencePlayer.GetQuestStatus(reqValue) != QuestStatus.Complete)
diff --git a/Source/Game/Conditions/ConditionManager.cs b/Source/Game/Conditions/ConditionManager.cs
index c0c5738bf..7c29540b1 100644
--- a/Source/Game/Conditions/ConditionManager.cs
+++ b/Source/Game/Conditions/ConditionManager.cs
@@ -2066,11 +2066,7 @@ namespace Game
                     results[i] = true;
 
                 for (var i = 0; i < condition.PrevQuestID.Length; ++i)
-                {
-                    uint questBit = Global.DB2Mgr.GetQuestUniqueBitFlag(condition.PrevQuestID[i]);
-                    if (questBit != 0)
-                        results[i] = (player.m_activePlayerData.QuestCompleted[((int)questBit - 1) >> 6] & (1ul << (((int)questBit - 1) & 63))) != 0;
-                }
+                    results[i] = player.IsQuestCompletedBitSet(condition.PrevQuestID[i]);
 
                 if (!PlayerConditionLogic(condition.PrevQuestLogic, results))
                     return false;
diff --git a/Source/Game/Entities/Player/Player.Quest.cs b/Source/Game/Entities/Player/Player.Quest.cs
index 4d185a6ba..2c024f6ac 100644
--- a/Source/Game/Entities/Player/Player.Quest.cs
+++ b/Source/Game/Entities/Player/Player.Quest.cs
@@ -2415,6 +2415,20 @@ namespace Game.Entities
             RemoveUpdateFieldFlagValue(questLog.ModifyValue(questLog.ObjectiveFlags), 1u << objectiveIndex);
         }
 
+        public bool IsQuestCompletedBitSet(uint questId)
+        {
+            uint questBit = Global.DB2Mgr.GetQuestUniqueBitFlag(questId);
+            if (questBit == 0)
+                return false;
+
+            int fieldOffset = (int)(questBit - 1) / ActivePlayerData.QuestCompletedBitsPerBlock;
+            if (fieldOffset >= m_activePlayerData.BitVectors.GetValue().Values[(int)PlayerDataFlag.CharacterQuestCompletedIndex].Values.Size())
+                return false;
+
+            ulong flag = 1ul << (((int)questBit - 1) % ActivePlayerData.QuestCompletedBitsPerBlock);
+            return (m_activePlayerData.BitVectors.GetValue().Values[(int)PlayerDataFlag.CharacterQuestCompletedIndex].Values[fieldOffset] & flag) != 0;
+        }
+
         void SetQuestCompletedBit(uint questBit, bool completed)
         {
             if (questBit == 0)
@@ -2425,7 +2439,7 @@ namespace Game.Entities
             if (fieldOffset < ActivePlayerData.QuestCompletedBitsSize)
             {
                 if (completed)
-                    SetUpdateFieldFlagValue(ref m_values.ModifyValue(m_activePlayerData).ModifyValue(m_activePlayerData.QuestCompleted,fieldOffset), flag);
+                    SetUpdateFieldFlagValue(ref m_values.ModifyValue(m_activePlayerData).ModifyValue(m_activePlayerData.QuestCompleted, fieldOffset), flag);
                 else
                     RemoveUpdateFieldFlagValue(ref m_values.ModifyValue(m_activePlayerData).ModifyValue(m_activePlayerData.QuestCompleted, fieldOffset), flag);
             }