diff --git a/docs/ISSUES.md b/docs/ISSUES.md
index f05c933e..7f15f3c3 100644
--- a/docs/ISSUES.md
+++ b/docs/ISSUES.md
@@ -158,6 +158,17 @@ resolution.
 
 ---
 
+## #343 — Shutdown after a wounded render loop: Silk Reset called inside the render loop, exit 82
+
+**Status:** OPEN. LOW-MEDIUM — only reachable after a render-frame exception
+(#339's crash was the trigger), but it turns a diagnosable failure into an
+`AbandonedIncomplete` shutdown. `GameWindowLifetime.ReleaseNativeWindow:294`
+calls `ViewImplementationBase.Dispose` → `Reset` while the render loop is
+formally still active. Fix belongs with the #339 remediation session.
+**Filed:** 2026-08-07 evening, from `session-b-dungeon.log`.
+
+---
+
 ## #341 — AD-66's landing is blocked by an unexplained measurement flip on the #331 absorb scenario
 
 **Status:** OPEN — HIGH priority for the next physics session; the fix itself
@@ -283,7 +294,56 @@ isolation.
 
 ---
 
-## #339 — Stuck in portal space: the destination reveal generation never becomes ready
+## #339 — Stuck in portal space / at login: the reveal never becomes ready — MECHANISM CAUGHT 2026-08-07 evening, full stack
+
+**BREAK: the crash is caught.** The Session-B gate launch reproduced the hang
+at LOGIN (cell 0xA8B4002F, all readiness flags False forever) and this time
+the log carries an unhandled `System.OverflowException` with a full stack:
+
+```
+ObjectMeshManager.PrepareMeshDataAsync    (ObjectMeshManager.cs:1028 region)
+  <- EnsureRenderDataReady:1302
+  <- WbMeshAdapter.IsRenderDataReady:340
+  <- LandblockSpawnAdapter.IsLandblockRenderReady:147
+  <- GpuWorldState.IsRenderReady:180
+  <- StreamingController.IsRenderNeighborhoodResident:280
+  <- WorldRevealReadinessBarrier.Prepare:142
+  <- WorldRevealCoordinator.PrepareAndEvaluate:188
+  <- RuntimeRenderFrameLivePreparation.Prepare
+```
+
+**The defect:** `PrepareMeshDataAsync` line ~1082 does
+`checked((uint)id)` on the Setup/GfxObj arm. EnvCell GEOMETRY ids are packed
+64-bit; they are supposed to take the EnvCell arm via `_envCellDescriptors`.
+`EnsureRenderDataReady` (line 1302) reaches the fallback when the id is
+**owned but descriptor-less**: the release path (`~line 712`) removes the
+descriptor while resident render data parks on the LRU; a re-acquire restores
+ownership, but nothing re-registers the descriptor until a full EnvCell
+prepare is re-requested. A readiness probe arriving in that window falls into
+the 32-bit cast and the OverflowException rides the RENDER FRAME path —
+after which the reveal is never evaluated again. Demote-then-revisit
+ordering explains the intermittency and why the same destination passed
+twice earlier: the window only exists after an evict/re-acquire cycle.
+
+**Status: mechanism established; ROOT-CAUSE FIX NOT YET DESIGNED.** The fix
+is NOT "catch the exception" and NOT "skip 64-bit ids" (band-aids both):
+the acquire/re-request ordering must make owned-implies-descriptor an
+invariant again, or EnsureRenderDataReady must legitimately re-request the
+EnvCell prepare from its own retained request data. Next session designs it
+against the acquire path (`_ownership` acquire sites vs descriptor
+registration at line 965). The S1B/S2 landings are NOT implicated — neither
+touches this pipeline, and the readiness signature predates both (the
+original filing below).
+
+**Also spun off this crash: #343** — the shutdown after the wounded render
+loop threw `InvalidOperationException: You cannot call Reset inside of the
+render loop!` (`GameWindowLifetime.ReleaseNativeWindow:294`), exit 82,
+`status=AbandonedIncomplete, blocked=native window`. Secondary, filed
+separately below.
+
+**Original filing:**
+
+## #339 (original) — Stuck in portal space: the destination reveal generation never becomes ready
 
 **Status:** OPEN — observed live 2026-08-07, evidence captured. **Not chased**;
 user directed it be fixed later.