diff --git a/docs/re/structures/xbg7-mesh.md b/docs/re/structures/xbg7-mesh.md
index f66e8e1..571f188 100644
--- a/docs/re/structures/xbg7-mesh.md
+++ b/docs/re/structures/xbg7-mesh.md
@@ -438,11 +438,27 @@ before the change   both twins decode with mean_x = −66.83  → mirror bdy_02
 after  the change   both twins decode with mean_x = +66.83  → mirror bdy_01  (contradicts it)
 ```
 
-Neither is right: two distinct resources sharing one decode is itself the bug,
-and the mirror heuristic has been compensating for it. The runtime capture is
-ground truth, so a change that contradicts it does not ship — **the real fix must
-give each twin its own buffer**, after which the mirror rule can use each
-resource's own geometry.
+The runtime capture is ground truth, so a change that contradicts it does not
+ship.
+
+**Correction (measured after the fact):** the first write-up of this said "two
+distinct resources sharing one decode is itself the bug". **That is wrong.**
+Sharing is normal here — 1 043 of 5 480 decoded resources (19 %) share geometry
+with another resource, and of 1 242 related pairs, **1 241 are identical in every
+container they co-occur in**, which is what legitimate asset reuse looks like.
+A mirrored pair like `bdy_01`/`bdy_02` is *supposed* to share one geometry, with
+the reflection applied at placement — exactly what `apply_twin_mirrors` does.
+
+What actually matters is **which of two mirrored buffers is canonical**. The disc
+holds both an X+ and an X− version; the engine treats one as the base, and
+`apply_twin_mirrors` was tuned against that. The neighbourhood anchor moved these
+resources to the *nearer* buffer, which is the other one — hence the flip. So the
+real fix is not "give each twin its own buffer" but **pin which buffer is
+canonical**, with the capture as the oracle.
+
+**Exactly one pair is provably mis-anchored by this test**: `e105_bdy_02_l` /
+`e105_brg_m` share a decode in 7 of the 15 containers holding both and differ in
+the rest — two names cannot be the same geometry only sometimes.
 
 **The filtered path needed care.** `models_named` (what the viewer's ship
 rendering uses) drops non-wanted resources, which would leave a filtered decode