End of August hit our account hard. Five consecutive days of deteriorating performance with zero changes on our end - same creatives, same audiences, same bid strategy we've run for four years at 50k+/day. The decay curve doesn't match typical fatigue patterns, it's a step-function drop starting August 24th.

First instinct was platform instability. A colleague mentioned similar crashes across a handful of accounts the same week, mid-month stable then floor dropped out. That aligns with what we're seeing: CPMs holding steady, CTR halved, CPA doubled overnight.

Pulled the diagnostic sequence we run when attribution goes silent:

-- Pixel event integrity check
SELECT event_name, COUNT(*) as fires,
 COUNT(DISTINCT user_id) as unique_users,
 DATE(event_time) as event_date
FROM pixel_events
WHERE event_time >= '2024-08-20'
GROUP BY event_name, DATE(event_time)
ORDER BY event_date DESC,

Events firing clean. No deduplication spikes. Browser-side CAPI payloads matching server-side within 2% variance.

Next, creative fatigue analysis. Another contact noted Meta's content fatigue algorithm turned significantly more aggressive this year - static assets decaying faster than video across their portfolio. Our mix is 70% static UGC-style imagery, 30% short-form video. Swapping fresh UGC clips (even rough cuts) into the top ad sets tonight as a controlled test.

If CPM trends hold stable through the swap and CTR recovers, it's creative-side algorithmic suppression, not auction dynamics. If CPMs spike concurrently, we're looking at inventory quality shift or bidding landscape change.

Running the creative refresh in a duplicated campaign with 10% budget allocation first - isolates variable without torching the main spend. Will know within 48 hours whether the fatigue hypothesis holds or we're dealing with something deeper in the attribution stack.