CBO dumping 90% of budget into one ad set and you panicked?

CBO dumping 90% of budget into one ad set and you panicked?

Don't kill the starved ad sets. That's CBO (campaign budget optimization — Meta splits spend itself) doing its job. The mistake is fighting it with manual overrides.

What people break it with:

— Setting minimum spend caps per ad set (handcuffs the algo)
— Pausing the 'losers' on day 1 before they get tested
— Editing budget mid-learning and forcing a reset

The fix: leave it alone 3-4 days. If an ad set truly gets zero spend across that window, THEN cut it.

Uneven spend in CBO isn't a bug. Try sitting on your hands for 72h.