diff --git a/docs/FRICTION.md b/docs/FRICTION.md
index e6f2b36..a3c64e4 100644
--- a/docs/FRICTION.md
+++ b/docs/FRICTION.md
@@ -68,3 +68,12 @@ earning its keep.
   language ("choice deferred", "pending", "TBD", the placeholder's name) and reconcile
   every hit — don't rely on the plan's file-map alone. Worth a `/review-repo` check for
   lingering "deferred/pending/TBD" references whose ADR has since resolved.
+  - **Recurred a 3rd time (same day):** ADR-017 resolved the browser-E2E harness but
+    left ADR-015's own "Deferred" list item #2 still reading as open — not caught by the
+    ADR-017 plan's sweep (which only checked for *its own* placeholder language), only
+    by a later STATUS pass. Lesson sharpened: the stale reference often lives in the
+    **originating ADR's Deferred section**, which the resolving ADR's plan won't think
+    to grep. → When an ADR resolves another ADR's deferred item, edit that **source
+    ADR's Deferred list** in the same change. Three hits now — promote from "worth a
+    check" to **build it**: a `/review-repo` rule flagging any ADR "Deferred/Open" entry
+    whose subject is named as RESOLVED/DECIDED elsewhere.