Tester got blamed
The release went live at 4:00 pm.
At 4:07 pm, customers could no longer log in.
At 4:12 pm, the project manager asked why testing had missed it.
The tester opened the test evidence. Login had passed every day for two weeks. The defect appeared only after someone changed the authentication settings during deployment.
Nobody had told testing about the change.
The developer blamed the deployment process. The deployment team blamed the ticket. The project manager blamed communication.
By 4:30 pm, everyone agreed on the root cause.
The tester should have predicted it.