I have confirmed the drift. Let me walk through the analysis.

**Phase 1–3 — Drift on completed task fn-9.1**

| Aspect | Spec (fn-9.1) said | Actually built (commit b3be2c4) |
|--------|--------|--------|
| `render_summary(items)` return | PLAIN TEXT, newline-joined, one item per line | JSON document — `json.dumps({"items": items})` |

Confirmed in `src/report/render.py:7`: `return json.dumps({"items": items})`. The done summary states it explicitly: structured/machine-readable output replaced the plain-text lines the spec described.

**Phase 3b — Husk short-circuit applies.** `GLOSSARY_JSON.total_terms == 0`, `DECISIONS_JSON.count == 0`, and `STRATEGY_CONTENT == {}` all hold → entire Phase 3b skipped (no glossary/decision/strategy signal to align to).

**Phase 4 — Downstream fn-9.2 references the stale contract.** fn-9.2 assumes render_summary emits plain text and splits it on newlines:
- Line 8: "Split the plain-text output of render_summary on newlines and mail each line."
- Line 13 (acceptance): "parses the plain-text output of render_summary into mail lines"

`json.dumps` produces a single newline-free string, so the newline-split integration point is now broken. This is a genuine stale reference (the *how* to consume render_summary's output), not a scope/requirement change — mailing each item remains the intent.

**Phase 4b** — CROSS_SPEC false → skipped.

**Phase 5 (DRY_RUN=true)** — report only, no edits. Parent spec `fn-9.md` has no `## Requirement coverage` table → traceability sub-step skipped. (Note: `fn-9.md`'s Approach line "fn-9.1 renders plain-text summaries" is also stale, but spec edits are restricted to the traceability table, so it is out of scope for edits.)

---

Drift detected: yes
- fn-9.1: `render_summary(items)` returns a JSON document `{"items": [...]}` (`json.dumps`) instead of the newline-joined plain text the spec described.

Would update (DRY RUN):
- **fn-9.2** (`.flow/tasks/fn-9.2.md`):
  - Description (line 8): "Split the plain-text output of render_summary on newlines and mail each line." → parse the JSON document `{"items": [...]}` returned by `render_summary` and mail each item.
  - Acceptance (line 13): "parses the **plain-text** output of render_summary into mail lines" → "parses the **JSON** output of render_summary into mail lines".
  - Add breadcrumb: `<!-- Updated by plan-sync: fn-9.1 returns JSON document {"items":[...]} not plain-text lines -->`

Would update traceability: none (no `## Requirement coverage` table in fn-9.md).

No decision overrides flagged (DECISIONS_JSON husk). No strategy drift flagged (STRATEGY_CONTENT husk).

No files modified.