diff --git a/services/shared/sql_init.py b/services/shared/sql_init.py
index 65d2595..bc63bcc 100644
--- a/services/shared/sql_init.py
+++ b/services/shared/sql_init.py
@@ -12,7 +12,7 @@ from services.shared.sql_models import Base
 
 
 _SCHEMA_INIT_LOCK = threading.Lock()
-_SCHEMA_INITIALIZED = False
+_BASE_SCHEMA_INITIALIZED = False
 
 
 def _table_columns(inspector, table_name: str) -> set[str]:
@@ -194,6 +194,7 @@ def _apply_runtime_schema_compatibility() -> None:
 
         if "whatsapp_messages" in table_names:
             columns = _table_columns(inspector, "whatsapp_messages")
+            _add_column_if_missing(conn, columns, "whatsapp_messages", "chat_id", "VARCHAR(128)")
             _add_column_if_missing(conn, columns, "whatsapp_messages", "thread_id", "VARCHAR(64)")
             _add_column_if_missing(conn, columns, "whatsapp_messages", "interaction_id", "VARCHAR(64)")
             _add_column_if_missing(conn, columns, "whatsapp_messages", "customer_id", "VARCHAR(64)")
@@ -593,21 +594,16 @@ def _apply_runtime_schema_compatibility() -> None:
 
 
 def init_sql_schema() -> None:
-    global _SCHEMA_INITIALIZED
-    if _SCHEMA_INITIALIZED:
-        return
+    global _BASE_SCHEMA_INITIALIZED
     with _SCHEMA_INIT_LOCK:
-        if _SCHEMA_INITIALIZED:
-            return
         if schema_management_mode() == "migrations":
             validate_schema_migrations_applied()
-            _SCHEMA_INITIALIZED = True
-            return
-        Base.metadata.create_all(bind=engine)
+        elif not _BASE_SCHEMA_INITIALIZED:
+            Base.metadata.create_all(bind=engine)
+            _BASE_SCHEMA_INITIALIZED = True
         for attempt in range(5):
             try:
                 _apply_runtime_schema_compatibility()
-                _SCHEMA_INITIALIZED = True
                 return
             except OperationalError as exc:
                 if "database is locked" not in str(exc).lower() or attempt >= 4:
diff --git a/tests/test_sql_init_compat.py b/tests/test_sql_init_compat.py
index 74ea2db..f92b723 100644
--- a/tests/test_sql_init_compat.py
+++ b/tests/test_sql_init_compat.py
@@ -42,7 +42,6 @@ def test_init_sql_schema_backfills_whatsapp_message_runtime_columns():
                 CREATE TABLE whatsapp_messages (
                   id INTEGER PRIMARY KEY AUTOINCREMENT,
                   message_id VARCHAR(64) NOT NULL UNIQUE,
-                  chat_id VARCHAR(128) NOT NULL,
                   text TEXT NOT NULL,
                   payload_json TEXT NOT NULL,
                   created_at VARCHAR(64) NOT NULL
@@ -58,6 +57,7 @@ def test_init_sql_schema_backfills_whatsapp_message_runtime_columns():
     indexes = {item["name"] for item in inspector.get_indexes("whatsapp_messages")}
 
     assert "thread_id" in columns
+    assert "chat_id" in columns
     assert "interaction_id" in columns
     assert "customer_id" in columns
     assert "delivery_status" in columns