diff --git a/src/AcDream.App/Rendering/GameWindow.cs b/src/AcDream.App/Rendering/GameWindow.cs
index 79a333b1..6bb93d10 100644
--- a/src/AcDream.App/Rendering/GameWindow.cs
+++ b/src/AcDream.App/Rendering/GameWindow.cs
@@ -7724,6 +7724,15 @@ public sealed class GameWindow : IDisposable
                     datBundle.Setups.TryGetValue(src, out var datSetup);
                     if (datSetup is not null && datSetup.Lights.Count > 0)
                     {
+                        // #176 site-A light-stacking leak: a landblock can RE-apply
+                        // without an unload in between (#168 ForceReloadWindow, Far→Near
+                        // promotion), and static entity ids are deterministic — so each
+                        // re-apply appended another copy of the same lights under the
+                        // same owner (observed ×2→×4 per session; the wash intensifies
+                        // over time, and the stacked ties destabilize the 128-cap pool
+                        // sort). Clear the owner's previous registration first: the
+                        // re-apply becomes idempotent, and a first apply is a no-op.
+                        _lightingSink.UnregisterOwner(entity.Id);
                         var loaded = AcDream.Core.Lighting.LightInfoLoader.Load(
                             datSetup,
                             ownerId: entity.Id,