The likely failure is a contract mismatch around defaults, config files, environment variables, command-line flags, remote configuration, secrets, merge order, null/empty semantics, reloads, and explainable effective values. I would reconstruct one canonical invariant, identify the layer violating it, apply the smallest bounded repair, and add deterministic boundary/failure/control tests. Existing security and product policy would be preserved. If repository files are available I can map the repair to exact paths; otherwise I would provide concrete pseudocode and a verification plan without claiming execution.