The page says chunking has degraded retrieval quality in the internal knowledge-base bot. What that actually means is explained by the trace: on call sees a plausible response, a successful vector query, and citations that point to the right handbook but the wrong passage. Nothing is down. The retrieval unit is wrong. TL;DR: chunking decides what a match can possibly be about. A chunk that mixes two topics matches both weakly; a chunk that splits an answer across a boundary may match neither ...