diff --git a/docs/TODO.md b/docs/TODO.md
index b6ccca1..829d868 100644
--- a/docs/TODO.md
+++ b/docs/TODO.md
@@ -81,6 +81,13 @@ Captured so nothing is lost while the article writing runs.
       default. Systems rolls up through the symptom keyword's parent and states
       its own coverage (1,502 of 2,948 questions). "Practise this topic" works
       on whichever axis the row came from.
+- [x] **Questions filed at system level, promoted** — done 2026-09-12. The
+      taxonomy rebuild regressed a previously-closed item: merges moved 108
+      questions up onto a root topic. All 108 promoted with zero ambiguous
+      cases; the remaining 146 sit at system level because no condition inside
+      that system exists to hold them, which is a classification gap rather
+      than a filing error. `Radial Head Subluxation` merged into
+      `Nursemaid's Elbow (Radial Head Subluxation)` — one idea under two names.
 - [ ] **Adaptive session** — the design and its weaknesses are written up in
       `docs/study-recommendations.md`; two defects fixed (a 2,000-row cap that
       hid a third of the bank, and an O(n·m) category lookup). Still open: