[2026-10-16] eagle: work/projects/cpm-metrics-causes-and-mitigations-2026-10-16.md

work/projects/cpm-metrics-causes-and-mitigations-2026-10-16.md

@@ -49,7 +49,7 @@ Percentages below are shares of all initial-failure / stuck daily reports in the
 - **P4, first mid-session load:** Fix A signature — **iOS init 3.9%, stuck 0.9%**. Broader recent-load cohort: **iOS init 15.7%, stuck 6.0%; macOS init 20.0%, stuck 6.4%**. early init loss is reproduced; Fix A waits for first background readiness. The narrower signature is 129k → 4.6k iOS reports and can include reloads.
 - **P5, tab registration lost:** separate shares of all init/stuck reports are unavailable. closing a window containing a shared pinned tab makes WebKit unregister the surviving tab. Correct window/tab lifecycle reporting is the mitigation to develop. The mechanism covers macOS `tab_in_context=false`; other P5 cases remain unexplained. Separate 14 October selection: **13.6% (68 of 499)** of selected macOS P5 stuck reports have that flag; the earlier 494-report selection used different filters.
 - **P6, controller mismatch:** broader detached-tab cohort — **iOS init 0.03%, stuck 0.05%; macOS init 6.2%, stuck 8.9%**. P6-only init/stuck shares are unavailable. a main `webExtensions` flag cycle creates a new manager while existing web views retain the old controller. Recreate/rebind affected views when replacing the manager; context reload alone cannot repair this. The conditional mechanism is reproduced, but its occurrence in production is unconfirmed. Selected macOS tails: **627 + 235** reports.
-- **Other:** **iOS init 5.3%, stuck 12.5%; macOS init 23.4%, stuck 22.2%**. no established cause. Readiness timing, init progress and healthy-load baselines are needed before selecting a mitigation.
+- **Other:** **iOS init 5.3%, stuck 12.5%; macOS init 23.4%, stuck 22.2%**. Residual snapshot category, with several candidate mechanisms. The iOS analysis found P1-like wake traces with views older than the 30-second classification cutoff. In `cpm-e2e-init`, an imposed 8-second native-settings delay produces `init_stage=received`, timeout and same-document recovery; withheld dashboard confirmation produces `response_sent` and timeout despite delivered page `initResp`. Injected message drops reproduce single-document and persistent one-tab, several-tab and all-window failures, including with valid tab/controller diagnostics. These tests establish diagnostic signatures and failure scope; natural triggers and shares within production Other remain unassigned. Suggested actions: test P1 readiness gating against older wake tails; measure native-settings latency for `received`; investigate dashboard delivery for `response_sent`; trace pre-background delivery for `none`. Use healthy readiness baselines and page receipt to distinguish them before choosing recovery.
 
 ## Open PRs and local validation