FAQ: Why Enterprise Backend Teams Are Discovering That Vector Database Index Drift Silently Corrupts RAG Retrieval Quality Across Tenant Boundaries After Foundation Model Embedding API Version Upgrades , And What to Rebuild Before It Hits Production

It starts with a support ticket. A tenant complains that your AI assistant is returning oddly irrelevant answers. Your team investigates, finds no obvious bug, and closes the ticket as "user error." Then another ticket arrives. And another. By the time your on-call engineer traces the root cause,