Google Said the Sale Didn't Happen. The Warehouse Shipped It Anyway.
Four campaigns bidding on the same product from the same platform can report a sale to the wrong one, and every number stays internally consistent while it happens.
Four campaigns, one product, one customer
A retailer selling the same catalog across four Shopping campaigns, each running its own target and budget, can end up bidding against itself for the exact same buyer. On two separate days, one brand-heavy campaign reported zero sales for a product that plainly sold. The revenue landed somewhere real. The credit landed in a different campaign next door.
The auction decided the winner, not the customer
Which campaign gets credit for a sale, when several of them are eligible to serve the same search term, depends on whose budget happened to have room and whose target happened to be reachable that morning, not on anything the buyer did. Campaign-level ROAS ends up reporting the platform's own internal routing back to the advertiser as if it were customer behavior, which is why moving a target on one campaign produces an unexplained swing on another.
Every number stays consistent while the sale goes to the wrong place
Nothing about this looks broken from inside the account. Each campaign's own math checks out; the platform just handed the transaction to the wrong ledger line. Fixing it inside the ad account is impossible, because every campaign involved is telling the truth about its own numbers. The only way to see which campaign earned a sale is a product-level record held somewhere the auction can't reach, checked against the order that shipped.