diff --git a/tests/Aetheria.Shared.Tests/ContactRevealTests.cs b/tests/Aetheria.Shared.Tests/ContactRevealTests.cs
index 4d39e28b6..5b5075042 100644
--- a/tests/Aetheria.Shared.Tests/ContactRevealTests.cs
+++ b/tests/Aetheria.Shared.Tests/ContactRevealTests.cs
@@ -644,6 +644,35 @@ public sealed class ContactRevealTests : IDisposable
         Assert.Equal(ended ? 0 : 1, o.RevealsOf(e).Count());
     }
 
+    // The gate is strict, as the light-act gate is: a light at removal that lands exactly on the threshold ends nothing.
+    // The signature is searched, a few floats either side of threshold over info, for the one whose product with the
+    // observer's info on the spot is exactly the threshold.
+    [Fact]
+    public void ADepartureExactlyAtTheLightActGateEndsNothing()
+    {
+        var e = Add(float3(0, 0, 100), new[] { "Gun" });
+        var o = Add(float3(0, 0, 0), new[] { "Eye" });
+        Fire(e, Guns(e)[0]);
+        Tick(.01f);
+        Assert.Single(o.RevealsOf(e));
+        var threshold = _items.GameplaySettings.TargetDetectionInfoThreshold;
+        var info = o.PassiveInfo(e.Position.xz, 1f);
+        var signature = threshold / info;
+        for (var step = 0; step < 8 && signature * info != threshold; step++)
+            signature = BitConverter.Int32BitsToSingle(BitConverter.SingleToInt32Bits(signature) + 1);
+        if (signature * info != threshold) signature = threshold / info;
+        for (var step = 0; step < 16 && signature * info != threshold; step++)
+            signature = BitConverter.Int32BitsToSingle(BitConverter.SingleToInt32Bits(signature) - 1);
+        Assert.True(signature * info == threshold, "fixture: a light exactly at the gate exists");
+        ShowOnly(e, signature, Guns(e)[0]);
+        Assert.True(e.Visibility * info == threshold, "fixture: the ship's light at removal is exactly the gate");
+
+        _zone.Entities.Remove(e);
+        Tick(.1f);
+
+        Assert.Single(o.RevealsOf(e));
+    }
+
     // A signature on the Emission channel (paint strength, a ping) is not light: it does not make a departure seen.
     [Fact]
     public void AnEmissionSignatureDoesNotMakeADepartureSeen()