Multimodal search performs well in evaluation, but employees report occasionally seeing snippets from documents they shouldn’t have access to. Where’s the bug?

The defect lies in the pipeline architecture rather than the filter logic itself. Because permissions are checked after fusion and reranking, restricted documents influence the merged ranking before they are removed. To fix this, you must move the permission check to the source selection stage, ensuring that restricted documents are excluded before any vector comparison or ranking occurs.