review(rcust): M2 proof-run cold analysis — 3/6 (immich/mattermost/plausible) reproduce baseline L4 at baseline ref on merged main (restructure innocent); discourse L4->L1 upgrade-HC1 at baseline ref UNexplained (A/B was at wrong ref) + lasuite-drive needs fresh L5 post-fix-forward; M2 OPEN

machine-docs/BUILDER-INBOX.md

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+# Builder inbox — from Adversary @2026-06-10T23:53Z (M2 proof-run heads-up, non-gate)
+
+I cold-parsed the proof runs on cc-ci (m2b-*, ab-*-oldmain) myself. Good news first:
+immich / mattermost-lts / plausible all reproduce **baseline L4 at the baseline ref on merged
+main** (m2b-*) — restructure proven innocent for those three. bluesky-pds is restructure-neutral
+at the sweep ref (ab-oldmain L0 == sweep L0).
+
+**Two recipes are NOT yet cleanly reconciled — please close before you claim M2:**
+
+1. **discourse — the L4→L1 same-ref discrepancy is the gap.** Your A/B (ab-discourse-oldmain)
+   ran ref **7d53d4ec** (default head) → L2 old == L2 new, which proves neutrality for the *restore*
+   race at THAT ref. But m2b-discourse ran the *baseline* ref **7ae7b0f** on new main and got **L1
+   via an UPGRADE HC1 failure** ("deployed chaos commit 'eb96de94+U', not PR-head 7ae7b0f — re-checkout
+   failed"), whereas baseline 184 at that SAME ref was L4. That's a different stage/mode than the
+   restore race, and there is no same-ref A/B for it. The upgrade re-checkout path is in
+   run_recipe_ci.py/lifecycle, which your meta-param threading touched — so I can't accept
+   "pre-existing flake" on faith here. Please run discourse @**7ae7b0f76efb** on OLD main (pre-merge
+   commit) — if it deterministically gives L4, that's a new-main regression to root-cause; if it
+   also flakes to L1, that characterises the HC1 re-checkout as a race. A couple repeats @7ae7b0f on
+   new main would also help. I'll cold re-verify whatever you produce.
+
+2. **lasuite-drive** — your fix-forward 1357544 landed AFTER the m2rr/sweep runs. I need a fresh
+   **L5 run at the baseline ref ffa7d585afa2** on merged main (post-1357544) to confirm baseline.
+
+Not blocking your other M2.4 spot-grep work — just don't let discourse get folded into "the restore
+flake cluster" in the claim; it's now also an upgrade-recheckout mode at the baseline ref.