File R-607 (a sync that says 'no change' while the cache moves) and sharpen the audit

Found by the live run, not by reading: POST /api/sync answered 'nincs valtozas'
while the box's catalog cache HAD moved, and catalog_images stayed stale until a
separate rescan. Since CatalogImages is the one input CatalogOrder compares
against, the badge answers from a stale catalog for that window — and the session
nearly recorded a stale tag-ok badge as proof of the R-524 ahead arm.

Neither half is isolated, so the row records the observation, not a diagnosis.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

documentation/audits/UPDATE-ARC-STATE-2026-09-21.md

@@ -283,9 +283,20 @@ path exists and is an **empty stub**. The journal was at
 box's own recovery read it at the next boot — which is the proof that it was there all along.
 
 **It was caught by running `find` over the whole rootfs instead of trusting one constructed path**,
-and by demanding a positive control for the directory being searched. **An empty directory is not
-evidence of an absent file** — it is equally consistent with "you are looking at an unmounted stub".
-That is R-96 rule 3 in a new place.
+and by demanding a positive control for the directory being searched. Read from the right place, the
+journal held exactly what §6.1 promises: `phase: "pulling"`, `prev_pin: …2.4.0`. **An empty directory
+is not evidence of an absent file** — it is equally consistent with "you are looking at an unmounted
+stub". That is R-96 rule 3 in a new place.
+
+### A second instrument trap in the same run — and it nearly bought a false proof
+
+`POST /api/sync` answered **„nincs változás"** while the box's catalog cache file HAD moved to the new
+tag, and the API's `catalog_images` stayed at the old value until a separate `POST /api/stacks/rescan`.
+Since `CatalogImages` is the one input `stacks.CatalogOrder` compares against, **the badge answers
+from a stale catalog for that window** — and the session nearly recorded a `tag-ok` badge as proof of
+the R-524 ahead arm when the badge was merely stale. The honest reading came only after the rescan.
+**An instrument that can report an old value as a current one is not a measurement.** Filed as
+**R-607**; neither half of it was isolated, so the row records the observation, not a diagnosis.
 
 ---