A team defines its delivery pipeline with the AWS CDK v2 pipelines.CodePipeline construct. A year ago, while iterating on the pipeline, an engineer set selfMutation: false and deployed it with cdk deploy. Today a developer adds a Prod application stage with addStage(), pushes to the source branch, and watches the pipeline run: the synth step succeeds, but no Prod stage ever appears in the pipeline. The Prod account was already bootstrapped with --trust for the pipeline account. The team wants future pipeline changes to arrive through git push alone; one final manual deployment to fix the situation is acceptable.