diff --git a/src/game-lib/Events/GameEventType.cs b/src/game-lib/Events/GameEventType.cs
index 67708d8b..46126adb 100644
--- a/src/game-lib/Events/GameEventType.cs
+++ b/src/game-lib/Events/GameEventType.cs
@@ -25,6 +25,8 @@ public class GameEventType
 
     public static bool IsValidPlayerActionEvent(string type) => PlayerActionName.IsValid(type);
 
+    public bool IsNotTimeAdvancement => ToString() != nameof(AdvanceTimePlayerAction);
+
     public GameEventType(string type)
     {
         Contract.Assert(IsValidWorldEventType(type) || IsValidPlayerActionEvent(type));
diff --git a/src/game-lib/State/GameSessionTurn.cs b/src/game-lib/State/GameSessionTurn.cs
index 932c7ea3..8832a9a5 100644
--- a/src/game-lib/State/GameSessionTurn.cs
+++ b/src/game-lib/State/GameSessionTurn.cs
@@ -55,9 +55,9 @@ public void AssertInvariants()
             "Number of events in turn must match the number of updates between the game states.");
 
         Contract.Assert(EventsUntilStartState.Last().Type.ToString() == GameEventType.ReportEvent);
+        Contract.Assert(EventsInTurn.SkipLast(1).All(@event => @event.Type.IsNotTimeAdvancement));
         IdGen.AssertConsecutiveIds(GameEvents.ToList());
-        // kja all events in turn except the last one must be not AdvanceTime player action
-        // Contract.Assert(EventsInTurn.SkipLast(1).All(@event => @event.Type == "a"))
+        
         StartState.AssertInvariants();
         EndState.AssertInvariants();
     }