diff --git a/tests/conftest.py b/tests/conftest.py
index b8733e0..be692d5 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -166,6 +166,17 @@ def _reset_db_after_integration(request, _truncate_engine):
             rows = (_SEED_SNAPSHOT or {}).get(t.name)
             if rows:
                 conn.execute(t.insert(), rows)
+                # Restored rows carry their explicit ids while RESTART
+                # IDENTITY reset the sequence to 1, so the next ORM insert
+                # would collide on the PK (bitten by migration 0075's seeded
+                # system tags: every Tag insert failed with pk_tag id=1).
+                # Resync any serial id sequence past the restored rows.
+                if "id" in t.c:
+                    conn.exec_driver_sql(
+                        f"SELECT setval(pg_get_serial_sequence('{t.name}', 'id'), "
+                        f"(SELECT COALESCE(MAX(id), 1) FROM {t.name})) "
+                        f"WHERE pg_get_serial_sequence('{t.name}', 'id') IS NOT NULL"
+                    )
 
 
 @pytest_asyncio.fixture(autouse=True)