diff --git a/src/api/router/snapshot_objects_bounded_tests.rs b/src/api/router/snapshot_objects_bounded_tests.rs
index 6475c53a..d001de12 100644
--- a/src/api/router/snapshot_objects_bounded_tests.rs
+++ b/src/api/router/snapshot_objects_bounded_tests.rs
@@ -264,7 +264,7 @@ async fn every_alias_is_admitted_and_exact_oid_body_is_loaded_once() {
             .send("POST", "objects", Body::from(request.to_string()))
             .await,
         409,
-        "DIGEST_MISMATCH",
+        "EXPECTED_DIGEST_MISMATCH",
         false,
     )
     .await;
@@ -314,7 +314,7 @@ async fn conflicting_sizes_reject_before_io_and_distinct_oids_still_verify_each_
             .send("POST", "objects", Body::from(request.to_string()))
             .await,
         409,
-        "DIGEST_MISMATCH",
+        "EXPECTED_DIGEST_MISMATCH",
         false,
     )
     .await;
@@ -388,7 +388,7 @@ async fn truncated_wrong_sha_and_late_stream_error_never_produce_200() {
         (
             FaultKind::Parts(vec![Bytes::from(vec![0; 8192])]),
             409,
-            "DIGEST_MISMATCH",
+            "EXPECTED_DIGEST_MISMATCH",
             8192,
         ),
         (
diff --git a/src/api/router/snapshot_storage_route_fixture.rs b/src/api/router/snapshot_storage_route_fixture.rs
index 751502b1..abc3aa48 100644
--- a/src/api/router/snapshot_storage_route_fixture.rs
+++ b/src/api/router/snapshot_storage_route_fixture.rs
@@ -65,8 +65,8 @@ pub(super) async fn reject_half_lease_commit_for_test(
         .await
         .unwrap();
     // Simulate an omitted derived write; all statement, identity and deferred
-    // completeness guards remain active, and the deriving trigger is restored
-    // before the actual commit attempt.
+    // completeness guards remain active. Failed commit rolls back the trigger
+    // change; pending deferred events forbid ALTER TABLE before commit.
     txn.execute_unprepared(
         "ALTER TABLE mst2_snapshot_lease DISABLE TRIGGER mst2_route_lease_insert",
     )
@@ -91,12 +91,28 @@ pub(super) async fn reject_half_lease_commit_for_test(
         .unwrap();
     assert_eq!(half.try_get::<i64>("", "actual").unwrap(), 1);
     assert_eq!(half.try_get::<i64>("", "routes").unwrap(), 0);
-    txn.execute_unprepared(
-        "ALTER TABLE mst2_snapshot_lease ENABLE TRIGGER mst2_route_lease_insert",
-    )
-    .await
-    .unwrap();
-    assert_eq!(trigger_modes(&txn).await, before);
+    let paused = before.replacen(
+        "mst2_snapshot_lease:mst2_route_lease_insert:O",
+        "mst2_snapshot_lease:mst2_route_lease_insert:D",
+        1,
+    );
+    assert_ne!(paused, before);
+    assert_eq!(trigger_modes(&txn).await, paused);
+    let complete = txn
+        .query_one_raw(Statement::from_string(
+            DbBackend::Postgres,
+            "SELECT t.tgenabled::text AS mode,t.tgdeferrable AS deferrable,t.tginitdeferred AS deferred
+         FROM pg_catalog.pg_trigger t WHERE t.tgrelid='mst2_snapshot_lease'::regclass
+           AND t.tgname='mst2_route_complete' AND NOT t.tgisinternal",
+        ))
+        .await
+        .unwrap()
+        .unwrap();
+    let mode: String = complete.try_get("", "mode").unwrap();
+    assert!(matches!(mode.as_str(), "O" | "A"));
+    assert!(before.contains(&format!("mst2_snapshot_lease:mst2_route_complete:{mode}")));
+    assert!(complete.try_get::<bool>("", "deferrable").unwrap());
+    assert!(complete.try_get::<bool>("", "deferred").unwrap());
     let rejected = txn.commit().await.unwrap_err();
     assert!(
         rejected
diff --git a/src/api/router/snapshot_storage_route_tests.rs b/src/api/router/snapshot_storage_route_tests.rs
index bd8df6f9..25d40ec3 100644
--- a/src/api/router/snapshot_storage_route_tests.rs
+++ b/src/api/router/snapshot_storage_route_tests.rs
@@ -1038,7 +1038,7 @@ async fn mst2_generic_storage_routes_temp_prepare_shadow_rejects_qualified_conte
         scalar(&txn, "SELECT count(*) FROM mst2_metadata_prepare").await,
         0
     );
-    assert_eq!(scalar(&txn, "SELECT (to_regclass('mst2_metadata_prepare')='pg_temp.mst2_metadata_prepare'::regclass)::bigint").await, 1);
+    assert_eq!(scalar(&txn, "SELECT CASE WHEN to_regclass('mst2_metadata_prepare')='pg_temp.mst2_metadata_prepare'::regclass THEN 1::bigint ELSE 0::bigint END").await, 1);
     let rejected = txn.execute_raw(statement(&format!(
         "INSERT INTO {schema}.mst2_snapshot_context(snapshot_id,canonical_descriptor,instance_id,commit_oid,
            root_tree_oid,metadata_root,prepare_id,publication_sequence,writer_epoch,certificate_receipt_id,authorization_epoch,state)