diff --git a/quest/m1/subscribe-ranges/ietf.md b/quest/m1/subscribe-ranges/ietf.md
index df78bd37c5..4b67081092 100644
--- a/quest/m1/subscribe-ranges/ietf.md
+++ b/quest/m1/subscribe-ranges/ietf.md
@@ -25,6 +25,12 @@ groups not supported") in `run_fetch_stream`
 refusal of a filter bounded by it ("FETCH relative to Largest Object not
 supported"): no filter, a relative start, or an absolute start with no end.
 
+The same FETCH-end path sets End of Track only when the read hits FIN, so a
+bounded FETCH that ends exactly at the track's last object reports
+`end_of_track: false` (found while landing #4971; it predates it). Set it only
+when the track has finished and the FETCH reaches its final object, never from
+a live track's Largest Object, and test both cases.
+
 ## Required
 
 - [Model ranges](/quest/m1/subscribe-ranges/model.md) - the range requests this answers