diff --git a/mcp-server/src/legal_mcp/services/learning_loop.py b/mcp-server/src/legal_mcp/services/learning_loop.py
index 14fa9a7..1b55217 100644
--- a/mcp-server/src/legal_mcp/services/learning_loop.py
+++ b/mcp-server/src/legal_mcp/services/learning_loop.py
@@ -149,14 +149,28 @@ async def process_final_version(
     # it (→ decision_lessons / appeal_type_rules, surfaced by T15) via the gate.
     # (Previously this auto-upserted every new_expression as a style_pattern —
     # that both bypassed the gate and contaminated style with substance. Removed.)
-    if pair_id is not None:
-        await db.update_draft_final_pair(
-            UUID(str(pair_id)),
-            final_text=final_text,
-            diff_stats=diff_stats,
-            analysis=analysis,
-            status="analyzed",
+    #
+    # create-or-update (INV-LRN4): normally mark-final already opened a
+    # 'final_received' pair, so we just advance it. For a case whose final
+    # pre-dates the mark-final snapshot mechanism (historical backfill) or a direct
+    # ingest_final_version call, no pair exists — open one now from the live blocks
+    # so the distillation is actually persisted instead of silently discarded.
+    # Caveat: the captured draft is the CURRENT blocks (possibly edited after
+    # sign-off), not a true mark-final snapshot.
+    if pair_id is None:
+        pair_id = await db.create_draft_final_pair(case_id, draft_text, "")
+        logger.info(
+            "process_final_version: no 'final_received' pair for case %s — opened one "
+            "from live blocks (backfill path; draft may post-date sign-off)",
+            case_id,
         )
+    await db.update_draft_final_pair(
+        UUID(str(pair_id)),
+        final_text=final_text,
+        diff_stats=diff_stats,
+        analysis=analysis,
+        status="analyzed",
+    )
 
     # Update decision + case status
     await db.update_decision(UUID(decision["id"]), status="final")