diff --git a/backend/app/workers/tasks/nspd_sync.py b/backend/app/workers/tasks/nspd_sync.py
index 2743a630..3c377919 100644
--- a/backend/app/workers/tasks/nspd_sync.py
+++ b/backend/app/workers/tasks/nspd_sync.py
@@ -125,11 +125,17 @@ _UPSERT_SQL = text(
         harvest_error, region_code
     ) VALUES (
         :quarter_cad,
-        CASE WHEN :geom_json IS NULL THEN NULL
-             ELSE ST_Multi(ST_Transform(ST_SetSRID(ST_GeomFromGeoJSON(:geom_json), 3857), 4326))
+        CASE WHEN CAST(:geom_json AS text) IS NULL THEN NULL
+             ELSE ST_Multi(ST_Transform(
+                     ST_SetSRID(ST_GeomFromGeoJSON(CAST(:geom_json AS text)), 3857), 4326))
         END,
-        CASE WHEN :bbox_xmin IS NULL THEN NULL
-             ELSE ST_MakeEnvelope(:bbox_xmin, :bbox_ymin, :bbox_xmax, :bbox_ymax, 3857)
+        CASE WHEN CAST(:bbox_xmin AS double precision) IS NULL THEN NULL
+             ELSE ST_MakeEnvelope(
+                     CAST(:bbox_xmin AS double precision),
+                     CAST(:bbox_ymin AS double precision),
+                     CAST(:bbox_xmax AS double precision),
+                     CAST(:bbox_ymax AS double precision),
+                     3857)
         END,
         :parcels_count, :buildings_count, :territorial_zones_count,
         :red_lines_count, :engineering_count, :zouit_count, :risks_count, :total_features,
diff --git a/backend/tests/test_nspd_sync.py b/backend/tests/test_nspd_sync.py
index 8b077cf6..c30b4496 100644
--- a/backend/tests/test_nspd_sync.py
+++ b/backend/tests/test_nspd_sync.py
@@ -25,6 +25,7 @@ from app.workers.tasks.nspd_sync import (
     _build_features_json,
     _build_risks_count,
     _build_zouit_count,
+    _upsert_dump,
     harvest_quarter,
     harvest_stale_quarters,
 )
@@ -71,6 +72,7 @@ def _make_dump(
         engineering_structures=[_make_feat("e1")],
         zouit=zouit,
         risks=risks,
+        opportunity={},
         layers_fetched=(
             "search",
             "parcels",
@@ -204,6 +206,7 @@ def test_harvest_quarter_empty_quarter(
         engineering_structures=[],
         zouit={"okn": [], "engineering": [], "natural": [], "protected": [], "other": []},
         risks={},
+        opportunity={},
         layers_fetched=("search",),
         bbox_3857=None,
         fetched_at_utc="2026-05-12T03:00:00+00:00",
@@ -365,6 +368,7 @@ def test_features_json_geometry_preserved() -> None:
         engineering_structures=[],
         zouit={},
         risks={},
+        opportunity={},
         layers_fetched=("search", "parcels"),
         bbox_3857=(100.0, 200.0, 300.0, 400.0),
         fetched_at_utc="2026-05-12T00:00:00+00:00",
@@ -375,3 +379,70 @@ def test_features_json_geometry_preserved() -> None:
     assert result[0]["layer"] == "parcels"
     assert result[0]["feature_id"] == "p1"
     assert result[0]["properties"] == {"k": "v"}
+
+
+# ── _upsert_dump CAST regression tests (#244) ────────────────────────────────
+
+
+@patch("app.workers.tasks.nspd_sync.SessionLocal")
+def test_upsert_dump_null_geom_executes_without_error(mock_session_cls: MagicMock) -> None:
+    """Regression #244: _upsert_dump с geom_json=None не падает на AmbiguousParameter.
+
+    psycopg3 не может вывести тип голого параметра $N внутри CASE WHEN ... IS NULL.
+    Fix: CAST(:geom_json AS text) IS NULL даёт явный тип — нет AmbiguousParameter.
+    """
+    mock_db = MagicMock()
+    mock_session_cls.return_value = mock_db
+
+    # dump=None → error-only path: все geo-параметры None, должен execute без ошибок
+    _upsert_dump(
+        quarter_cad="66:41:0204016",
+        region_code=66,
+        dump=None,
+        features_json=None,
+        duration_ms=100,
+        harvest_error="TestError: simulated",
+    )
+
+    mock_db.execute.assert_called_once()
+    mock_db.commit.assert_called_once()
+
+
+@patch("app.workers.tasks.nspd_sync.SessionLocal")
+def test_upsert_dump_with_geom_executes_without_error(mock_session_cls: MagicMock) -> None:
+    """Regression #244: _upsert_dump с реальным geom_json и bbox не падает.
+
+    CAST(:geom_json AS text) передаёт строку, CAST(:bbox_xmin AS double precision) —
+    число. Оба branch CASE WHEN типизированы корректно.
+    """
+    mock_db = MagicMock()
+    mock_session_cls.return_value = mock_db
+
+    geom = {
+        "type": "Polygon",
+        "coordinates": [
+            [[100.0, 200.0], [300.0, 200.0], [300.0, 400.0], [100.0, 400.0], [100.0, 200.0]]
+        ],
+    }
+    dump = _make_dump(
+        quarter_cad="66:41:0204016",
+        quarter_feat=_make_feat_with_geom("q1", geom),
+        bbox=(100.0, 200.0, 300.0, 400.0),
+    )
+
+    _upsert_dump(
+        quarter_cad="66:41:0204016",
+        region_code=66,
+        dump=dump,
+        features_json=_build_features_json(dump),
+        duration_ms=500,
+        harvest_error=None,
+    )
+
+    mock_db.execute.assert_called_once()
+    # Verify params contain properly-typed values (not None for geo fields)
+    call_params = mock_db.execute.call_args[0][1]
+    assert call_params["geom_json"] is not None  # JSON string
+    assert call_params["bbox_xmin"] == 100.0
+    assert call_params["bbox_ymax"] == 400.0
+    mock_db.commit.assert_called_once()