quest: re-scope cross-relay bursts as a wait quest plus an impaired two-relay drill

quest/m1/README.md

@@ -57,7 +57,8 @@ blocks. The quests that gated m0 lines moved under them.
 - [#2991](/quest/m1/2991-net-coalesce-dynamic-tracks-and-preserve-sequences-across.md) - one dynamic producer per track name in both languages, with the sequence namespace surviving a replacement
 - [Subscribe ranges](/quest/m1/subscribe-ranges/README.md) - a lite-07 SUBSCRIBE asks for past and live ranges in either order and replaces FETCH; relays fill misses by range, including over moq-transport
 - [Live media time](/quest/m1/subscribe-live-time.md) - re-scoped against `set_live`: a lite-07 SUBSCRIBE_OK carries the publisher's current media time only if a reader still needs it
-- [Cross-relay bursts](/quest/m1/cross-relay-bursts.md) - bursty small-group tracks cross two relays without lost groups, unanswered FETCHes, or stalls
+- [Cross-relay bursts re-run](/quest/m1/cross-relay-bursts.md) - condition: the #4349 reporter re-runs their A/B/C comparison against current cdn.moq.pro
+- [Two-relay drill on impaired links](/quest/m1/cross-relay-drill.md) - a bursty small-group track crosses two clustered relays over lossy, delayed, flow-limited QUIC without unanswered FETCHes or `Old` stalls
 - [Untimed lite-07](/quest/m1/lite-untimed.md) - lite-07 carries an untimed track in both languages; lite-05/06 write send time
 - [Finalize moq-lite-07](/quest/m1/lite07-finalize.md) - when the maintainer cuts it, lite-07 negotiates as `moq-lite-07` and the next release ships it
 - [Late lower groups](/quest/m1/lite-late-lower-group.md) - a moq-lite subscriber with a floor receives a group created below the first served one, as moq-transport does

quest/m1/cluster-routing/README.md

@@ -146,5 +146,5 @@ Once every child has landed:
 - [One route cost](/quest/m1/route-cost.md) - Warm and Cold collapse to one static cost
 - [Same-epoch importers](/quest/m1/hop-aligned-import.md) - the importer half of a redundant pair under one explicit epoch
 - [Broadcast epochs](/quest/m0/broadcast-epoch/README.md) - a redundant pair shares one epoch
-- [Cross-relay delivery under bursts](/quest/m1/cross-relay-bursts.md) - its #4349 report shows closed broadcasts announced for up to 229 s
+- [Cross-relay bursts re-run](/quest/m1/cross-relay-bursts.md) - its #4349 report shows closed broadcasts announced for up to 229 s
 - [Routing cost domains](/quest/m3/routing-cost-domains.md) - policy and aggregation at boundaries between operators

quest/m1/cross-relay-bursts.md

@@ -1,30 +1,43 @@
-# [L] Cross-relay delivery under bursts
+# [XS] Cross-relay bursts re-run
 
 ## Goal
 
-Bursty small-group tracks cross two relays without losing groups or stalling.
-On cdn.moq.pro, publishers and a subscriber on different nodes saw groups
-never arrive (FETCH for them unanswered for 2 s while the publisher stayed
-connected), a subscription opened early deliver only a burst's tail, and
-return tracks stall up to 31 s with `Stream(Old)`. The same workload on one
-node, or one self-hosted relay, loses nothing.
+Condition: the [#4349](https://github.com/moq-dev/moq/issues/4349) reporter
+re-runs their A/B/C comparison (different nodes, one node, self-hosted)
+against current cdn.moq.pro, and ideally shares their load harness, as asked
+in the 2026-10-06 maintainer reply.
 
-## Plan
+Check: a new comment on #4349 with the results, noting for each failed FETCH
+whether it ended in an error or a timeout.
+
+Once the condition clears, delete this quest. If the re-run still loses
+groups or stalls cross-node, replace it with a concrete repro quest built on
+their harness and move the `Closes` entry there; if it comes back clean,
+close #4349 in the deletion PR.
 
-Reproduce first, on a local two-relay cluster with the reporter's harness
-(offered in the issue) and the relay build cdn.moq.pro ran. Then fix what the
-repro shows. Suspects: `Old` expiry or newest-first dropping on the relay hop,
-and FETCH not forwarded or answered upstream. A group awaiting its FIN ack
-now expires and follows priority updates, which removed one candidate cause.
-Keep the repro as a regression test in the cluster tests.
+## Plan
 
-The issue's stale and flapping announcements after a clean close are
-cluster-routing evidence, not this quest's scope.
+Established by a mock two-relay repro (one-frame groups in bursts of 14, a
+subscription opened 5 s before the burst, fetch-on-gap with a 2 s deadline,
+a flapping peer link), run against the 0.15.6 tree the reporter's clients
+used and against `main`:
+
+- **Fixed.** Burst-start misses (one more group lost per relay hop) and
+  route-flap drops (about 70 of 560 groups) reproduce only on 0.15.6 and are
+  gone on moq-net 0.3.8 and later, most likely by #4387.
+- **Not reproduced.** Unanswered FETCHes and the 30 s `Stream(Old)` stalls
+  showed up on no build. The mock models neither loss nor flow control, so
+  [Two-relay drill on impaired links](/quest/m1/cross-relay-drill.md) covers
+  that gap. Several 30 s timers of that era have since been removed or
+  shortened (#4606, #4741).
+- **Expected.** Across relays a burst arrives newest-first, as the lite draft
+  specifies; fetching on every gap at once multiplies FETCHes.
 
 ## Closes
 
 - [#4349](https://github.com/moq-dev/moq/issues/4349) - close this issue when the quest finishes
 
 ## Related
 
+- [Two-relay drill on impaired links](/quest/m1/cross-relay-drill.md) - looks for the unreproduced FETCH and `Old` stalls without waiting on the reporter
 - [Routes and announces](/quest/m1/cluster-routing/routes.md) - owns the stale and flapping announcements from the same report

quest/m1/cross-relay-drill.md

@@ -0,0 +1,37 @@
+# [M] Two-relay drill on impaired links
+
+## Goal
+
+A real-QUIC test runs a bursty small-group track (one frame per group, bursts
+of tens of groups) from a publisher on one relay to a subscriber on a
+clustered second relay, with the links impaired by loss, delay, and
+flow-control pressure. It shows every group either arriving or failing by
+name within a bounded time: no FETCH left unanswered, and no track stalled
+by relay-hop `Old` resets. A failure it finds gets fixed at the cause, or a
+quest of its own if large.
+
+The mock two-relay harness behind
+[#4349](https://github.com/moq-dev/moq/issues/4349) cannot produce those
+resets, so the issue's unanswered FETCHes and 30 s `Stream(Old)` stalls are
+still unexplained.
+
+## Plan
+
+`rs/moq-relay/tests/drills.rs` already runs single-relay drills over real
+QUIC in a loopback and a `moq_shaper` impaired lane, and the cluster tests
+(`cluster_idle.rs`, `goaway_cluster.rs`) start peered relays in-process.
+Open for the planner:
+
+- A new drill in that file's lanes or a separate two-relay test, and which
+  hop or hops (client and peer links) get shaped.
+- How to apply flow-control pressure: tight QUIC windows, a rate limit below
+  the burst rate, or both.
+- The subscriber's recovery model: fetch-on-gap with a deadline, as the
+  reporter's app does, versus waiting and reordering locally.
+- Whether a burst plus a flapping peer link joins as a regression for the
+  0.15.6 losses fixed in moq-net 0.3.8.
+
+## Related
+
+- [Cross-relay bursts re-run](/quest/m1/cross-relay-bursts.md) - waits on the #4349 reporter's re-run against current cdn.moq.pro
+- [Routes and announces](/quest/m1/cluster-routing/routes.md) - the cluster routing a flapping peer link exercises