diff --git a/server/NeonSprawl.Server.Tests/Game/Npc/InMemoryNpcRuntimeStateStoreTests.cs b/server/NeonSprawl.Server.Tests/Game/Npc/InMemoryNpcRuntimeStateStoreTests.cs
index c54a31a..c4984a4 100644
--- a/server/NeonSprawl.Server.Tests/Game/Npc/InMemoryNpcRuntimeStateStoreTests.cs
+++ b/server/NeonSprawl.Server.Tests/Game/Npc/InMemoryNpcRuntimeStateStoreTests.cs
@@ -78,6 +78,8 @@ public sealed class InMemoryNpcRuntimeStateStoreTests
             Assert.Equal(NpcBehaviorState.Idle, snapshot.BehaviorState);
             Assert.Null(snapshot.ActiveTelegraph);
         }
+
+        Assert.Equal(DateTimeOffset.MinValue, store.LastAdvancedUtc);
     }
 
     [Fact]
diff --git a/server/NeonSprawl.Server.Tests/Game/Npc/NpcRuntimeOperationsTests.cs b/server/NeonSprawl.Server.Tests/Game/Npc/NpcRuntimeOperationsTests.cs
index eeb1107..430e108 100644
--- a/server/NeonSprawl.Server.Tests/Game/Npc/NpcRuntimeOperationsTests.cs
+++ b/server/NeonSprawl.Server.Tests/Game/Npc/NpcRuntimeOperationsTests.cs
@@ -258,4 +258,23 @@ public sealed class NpcRuntimeOperationsTests
         Assert.Equal(NpcBehaviorState.Recover, snapshot.BehaviorState);
         Assert.Equal(T0.AddSeconds(9), snapshot.PhaseStartedUtc);
     }
+
+    [Fact]
+    public void ResetAllPrototypeRows_ShouldClearLastAdvancedUtc_ForFreshAdvanceBaseline()
+    {
+        // Arrange
+        var (runtime, threat, behavior) = CreateFixture();
+        SetHolder(threat, PrototypeNpcRegistry.PrototypeNpcMeleeId);
+        Advance(T0, runtime, threat, behavior);
+        runtime.LastAdvancedUtc = T0.AddHours(1);
+        NpcRuntimeOperations.ResetAllPrototypeRows(runtime);
+        SetHolder(threat, PrototypeNpcRegistry.PrototypeNpcMeleeId);
+        // Act
+        Advance(T0.AddHours(1).AddSeconds(10), runtime, threat, behavior, maxDeltaSeconds: 5);
+        // Assert
+        runtime.TryGet(PrototypeNpcRegistry.PrototypeNpcMeleeId, out var snapshot);
+        Assert.Equal(NpcBehaviorState.Aggro, snapshot.BehaviorState);
+        Assert.Equal(T0.AddHours(1).AddSeconds(10), snapshot.PhaseStartedUtc);
+        Assert.Equal(T0.AddHours(1).AddSeconds(10), runtime.LastAdvancedUtc);
+    }
 }
diff --git a/server/NeonSprawl.Server/Game/Npc/InMemoryNpcRuntimeStateStore.cs b/server/NeonSprawl.Server/Game/Npc/InMemoryNpcRuntimeStateStore.cs
index 6a9d712..7ee4883 100644
--- a/server/NeonSprawl.Server/Game/Npc/InMemoryNpcRuntimeStateStore.cs
+++ b/server/NeonSprawl.Server/Game/Npc/InMemoryNpcRuntimeStateStore.cs
@@ -69,6 +69,8 @@ public sealed class InMemoryNpcRuntimeStateStore : INpcRuntimeStateStore
         {
             _ = TryResetPrototypeRow(npcInstanceId);
         }
+
+        LastAdvancedUtc = DateTimeOffset.MinValue;
     }
 
     private static string NormalizeNpcInstanceId(string? npcInstanceId) =>