diff --git a/UPDATING.md b/UPDATING.md
index 3d42f2b3d4e..527c32f846b 100644
--- a/UPDATING.md
+++ b/UPDATING.md
@@ -114,7 +114,6 @@ DISTRIBUTED_COORDINATION_CONFIG = {
 ```
 
 See `superset/config.py` for complete configuration options.
-
 ### WebSocket config for GAQ with Docker
 
 [35896](https://github.com/apache/superset/pull/35896) and [37624](https://github.com/apache/superset/pull/37624) updated documentation on how to run and configure Superset with Docker. Specifically for the WebSocket configuration, a new `docker/superset-websocket/config.example.json` was added to the repo, so that users could copy it to create a `docker/superset-websocket/config.json` file. The existing `docker/superset-websocket/config.json` was removed and git-ignored, so if you're using GAQ / WebSocket make sure to:
diff --git a/superset/engines/manager.py b/superset/engines/manager.py
index ed6700d4884..1beb41929af 100644
--- a/superset/engines/manager.py
+++ b/superset/engines/manager.py
@@ -320,7 +320,8 @@ class EngineManager:
         uri = make_url_safe(database.sqlalchemy_uri_decrypted)
 
         extra = database.get_extra(source)
-        kwargs = extra.get("engine_params", {})
+        # Make a copy to avoid mutating the original extra dict
+        kwargs = dict(extra.get("engine_params", {}))
 
         # get pool class
         if self.mode == EngineModes.NEW or "poolclass" not in kwargs:
@@ -336,7 +337,7 @@ class EngineManager:
             kwargs["poolclass"] = pools.get(extra["poolclass"], pool.QueuePool)
 
         # update URI for specific catalog/schema
-        connect_args = extra.setdefault("connect_args", {})
+        connect_args = dict(extra.get("connect_args", {}))
         uri, connect_args = database.db_engine_spec.adjust_engine_params(
             uri,
             connect_args,
diff --git a/tests/unit_tests/engines/manager_test.py b/tests/unit_tests/engines/manager_test.py
index 871624f2a42..dc5248d663a 100644
--- a/tests/unit_tests/engines/manager_test.py
+++ b/tests/unit_tests/engines/manager_test.py
@@ -22,7 +22,6 @@ from collections.abc import Iterator
 from unittest.mock import MagicMock, patch
 
 import pytest
-from sqlalchemy.pool import NullPool
 
 from superset.engines.manager import _LockManager, EngineManager, EngineModes
 
@@ -51,7 +50,7 @@ class TestLockManager:
         manager = _LockManager()
 
         # Create locks
-        lock1 = manager.get_lock("key1")
+        _ = manager.get_lock("key1")  # noqa: F841
         lock2 = manager.get_lock("key2")
 
         # Cleanup with only key1 active
@@ -111,7 +110,7 @@ class TestEngineManager:
         """Create a mock database."""
         database = MagicMock()
         database.sqlalchemy_uri_decrypted = "postgresql://user:pass@localhost/test"
-        database.get_extra.return_value = {"engine_params": {"poolclass": NullPool}}
+        database.get_extra.return_value = {"engine_params": {}}
         database.get_effective_user.return_value = "test_user"
         database.impersonate_user = False
         database.update_params_from_encrypted_extra = MagicMock()
@@ -231,7 +230,7 @@ class TestEngineManager:
         ssh_tunnel.server_address = "ssh.example.com"
         ssh_tunnel.server_port = 22
         ssh_tunnel.username = "ssh_user"
-        ssh_tunnel.password = "ssh_pass"
+        ssh_tunnel.password = "ssh_pass"  # noqa: S105
         ssh_tunnel.private_key = None
         ssh_tunnel.private_key_password = None
 
@@ -266,7 +265,7 @@ class TestEngineManager:
         ssh_tunnel.server_address = "ssh.example.com"
         ssh_tunnel.server_port = 22
         ssh_tunnel.username = "ssh_user"
-        ssh_tunnel.password = "ssh_pass"
+        ssh_tunnel.password = "ssh_pass"  # noqa: S105
         ssh_tunnel.private_key = None
         ssh_tunnel.private_key_password = None
 
diff --git a/tests/unit_tests/sql/execution/conftest.py b/tests/unit_tests/sql/execution/conftest.py
index 630f6884529..fba41e6e376 100644
--- a/tests/unit_tests/sql/execution/conftest.py
+++ b/tests/unit_tests/sql/execution/conftest.py
@@ -202,7 +202,6 @@ def setup_mock_raw_connection(
     def _raw_connection(
         catalog: str | None = None,
         schema: str | None = None,
-        nullpool: bool = True,
         source: Any | None = None,
     ):
         yield mock_connection