An answer that ends “Why: not stated”
Answers follow a shape. First the direct answer. Then a line beginning Why: with the mechanism behind it. Then the evidence. An answer that names records without the reason behind them is sent back once for its reasoning.
If the second attempt still gives no reason, the answer is shown with a closing line. It reads: Why: not stated — this answer names records without the mechanism behind them; open the cited records before relying on it. Nothing is invented to fill the gap.
Read such an answer as a list of pointers, not an explanation. Open the records it names, or ask the question again more narrowly.
Two kinds of answer owe no separate reason. A refusal (I don’t have sufficient information…) and an answer that begins Nothing visible to you indicates… rest on the search itself, and each says which records were consulted.