My Meta ROAS dropped from 3.1 to 1.8 in 4 days on cold broad audience with ₹3000/day. What should I check first?
Most likely audience fatigue on a small ad set. Check frequency first: if it crossed 3.5 over the last 7 days, rotate creatives before touching targeting. Second suspect is creative-level spend imbalance, if 60 percent or more of your spend is going to one ad the optimiser is tunnelling. Split the set into a fresh ABO with 3 new creatives and a CBO with your top performer at 60 percent exclusion.