Why did my CPA jump last week?

I pulled campaign-level performance for the last two weeks. Your account-level Meta CPA rose from $42.31 to $47.92 week over week (+13%), while spend only grew $7,700 → $8,050 — so this is an efficiency problem, not a scaling artifact.

One campaign is responsible for almost all of it:

• Retargeting — Cart 14d — CPA jumped from $44.15 to $60.97 (+38%). Its frequency climbed from 3.1 to 4.6 over the same window: the same cart abandoners are seeing the same ads nearly 5x a week, and they've stopped responding. Conversions fell 41 → 31 even though spend went up. This is classic retargeting creative fatigue.
• The other three campaigns moved single digits (Prospecting — Trail Jackets $42.03 → $45.81, Advantage+ — Core Catalog $39.25 → $42.16, Prospecting — Ridgeline Boots $46.67 → $48.75) — normal weekly noise.

Here's the daily CPA trend — you can see the drift start about a week ago:

What I'd do about it:

1. Pause the two most fatigued ads in Retargeting — Cart 14d — the ones that have run unchanged for 3+ weeks are dragging the whole campaign.
2. Refresh the creative. Ship 2–3 new variants (new hook, new visual — Creative Studio can spin up an A/B set from your Alpine Shell copy in a few minutes) so the audience sees something new before you touch budget.
3. Add a frequency guardrail. Keep an eye on it post-refresh; above ~3.5 this audience stops converting.

If retargeting just returns to its prior ~$44 CPA, blended account CPA lands back around $42.31 at current spend. Want me to draft the refresh brief?