Someone asks, "What does a Senior Engineer earn here?" Your chatbot answers. With citations. Nobody hacked anything. Similarity search found the HR salary chunk because that chunk lived in the same index as the travel policy. I keep seeing the same leaks in "docs chatbot" demos. The full working project (ASP.NET Core / .NET 10, Microsoft.Extensions.VectorData + Microsoft.Extensions.AI, tests, offline mode) is in Tech Skill Builder . This post is the short version: five mistakes that turn RAG...