diff --git a/docs/ISSUES.md b/docs/ISSUES.md
index 0e951a27..c4376a55 100644
--- a/docs/ISSUES.md
+++ b/docs/ISSUES.md
@@ -24,6 +24,33 @@ What does NOT go here:
 - Every session: scan OPEN issues at start; promote/close anything we touched during the session before ending.
 - Promoting to a Phase: mark as `DONE (promoted to Phase X)` + commit SHA where the Phase entry landed.
 
+## #421 — Directional-shadow pass uploads its own transform buffer instead of binding the main pass's instance SSBO
+
+**Status:** OPEN — filed 2026-08-22 at Campaign VM VM5 (post-M7 / with GPU culling).
+**Component:** rendering / render packs (Campaign AR Tier 2)
+
+**Description:** `DirectionalShadowTransformBufferSet`
+(`src/AcDream.App/Rendering/DirectionalShadowTransformBufferSet.cs`)
+re-composes every caster's world matrix from the same
+`MeshRef.PartTransform x LocalToWorld` inputs the main pass uses (same
+`WbDrawDispatcher.ComposePartWorldMatrix`, so there is no second pose —
+Campaign AR constraint 5 is honoured in spirit) and uploads them into a
+second GPU buffer each frame for the animated subset. This is where the
+65,536-matrix binding ceiling regression lived (fixed in Campaign AR
+Stage 1). Cost is measured small (0.11–0.21 ms CPU incremental on the
+reference matrix) but it is a duplicate of the N.5 instance SSBO the main
+pass already binds.
+
+**What to do:** when the planned GPU-culling step for shadow cascades
+lands (Campaign AR plan, "If that is too expensive, the next permitted
+step is GPU culling"), bind the main pass's instance transform SSBO for
+the caster pass instead of maintaining `DirectionalShadowTransformBufferSet`,
+and delete the set. Not before — the shared buffer's lifetime/flight
+rules differ (main pass ring vs retained caster topology) and unifying
+them without the culling redesign would just move the ceiling.
+Reference: Campaign AR review F7,
+`docs/research/2026-08-22-campaign-ar-review.md`.
+
 ## #420 — Client crashes on the character-select screen (`UiButton.OnDraw` null media-state key)
 
 **Status:** ✅ FIXED 2026-08-19, root cause proven by a reverting test.
diff --git a/docs/plans/2026-08-22-visualmaster-campaign.md b/docs/plans/2026-08-22-visualmaster-campaign.md
index 72e96722..70b5571e 100644
--- a/docs/plans/2026-08-22-visualmaster-campaign.md
+++ b/docs/plans/2026-08-22-visualmaster-campaign.md
@@ -81,7 +81,7 @@ single-pass path darkens by ~10 %. Neither explains a scene-wide level.
 | VM2 | F3 — which retail detail path ran | **CLOSED 2026-08-22** — single-pass; see [cdb note](../research/2026-08-22-vm2-retail-detail-path-cdb.md) |
 | VM3 | F4 — linear-light post stack | automated + **owner visual** |
 | VM4 | F5 — overclaiming docs, incl. the reviewer's own | **CLOSED 2026-08-22** |
-| VM5 | F8 — volumetric banding; F7 filed | automated |
+| VM5 | F8 — volumetric banding; F7 filed | **CLOSED 2026-08-22** (#421) |
 | VM6 | Foliage wind | automated + **owner visual** |
 | VM7 | Closeout: full gates, register, roadmap, merge | **owner** |
 
@@ -252,6 +252,9 @@ Add the VM0 numbers as the new baseline table. Docs only; no code.
 - File issue: the shadow pass uploads a second transform buffer; a future
   GPU-culling step should bind the main pass's instance SSBO. Not built here.
 
+**OUTCOME (2026-08-22):** IGN jitter landed in atmospheric_volumetric.frag
+(pack-on only); F7 filed as #421.
+
 ## VM6 — Foliage wind (the feature)
 
 ### What "real movement" means here
diff --git a/src/AcDream.App/Rendering/Shaders/atmospheric_volumetric.frag b/src/AcDream.App/Rendering/Shaders/atmospheric_volumetric.frag
index 94cd28ab..843fd0c2 100644
--- a/src/AcDream.App/Rendering/Shaders/atmospheric_volumetric.frag
+++ b/src/AcDream.App/Rendering/Shaders/atmospheric_volumetric.frag
@@ -52,10 +52,19 @@ void main()
     vec3 sceneWorld = reconstructWorld(vUv, sceneDepth);
     int steps = clamp(int(uPackParams0.z + 0.5), 1, 64);
     float lit = 0.0;
+    // Interleaved gradient noise (Jimenez, "Next Generation Post Processing
+    // in Call of Duty: Advanced Warfare", 2014). Every pixel would otherwise
+    // sample the same t values along its march, so shadow-cascade edge
+    // crossings line up between neighbouring pixels and read as visible
+    // concentric banding. Jittering the march's starting phase per pixel
+    // decorrelates those step boundaries, turning the banding into fine
+    // noise that the existing quarter/half-res upsample already averages
+    // away.
+    float ign = fract(52.9829189 * fract(dot(gl_FragCoord.xy, vec2(0.06711056, 0.00583715))));
     for (int step = 0; step < 64; ++step) {
         if (step >= steps)
             break;
-        float t = (float(step) + 0.5) / float(steps);
+        float t = (float(step) + ign) / float(steps);
         lit += directionalVisibility(mix(nearWorld, sceneWorld, t));
     }
 
diff --git a/src/AcDream.App/Rendering/Shaders/spv/atmospheric_volumetric.frag.spv b/src/AcDream.App/Rendering/Shaders/spv/atmospheric_volumetric.frag.spv
index d782ffe1..5ac257b8 100644
Binary files a/src/AcDream.App/Rendering/Shaders/spv/atmospheric_volumetric.frag.spv and b/src/AcDream.App/Rendering/Shaders/spv/atmospheric_volumetric.frag.spv differ
diff --git a/src/AcDream.App/Rendering/Shaders/spv/shaders.manifest.json b/src/AcDream.App/Rendering/Shaders/spv/shaders.manifest.json
index 9e1b750d..45208862 100644
--- a/src/AcDream.App/Rendering/Shaders/spv/shaders.manifest.json
+++ b/src/AcDream.App/Rendering/Shaders/spv/shaders.manifest.json
@@ -92,7 +92,7 @@
         },
         {
           "stage": "frag",
-          "sourceSha256": "8d6177707a95cf0230881bbfb7467c0591632eb67dce3c758596c83cafb14ffc",
+          "sourceSha256": "0195fa5fdfb3850e090bed6f144981d454edfed526b79efe8dd5300b610b2f0f",
           "compiled": true
         }
       ]