hopefully fixed strange session timeout behavior

config/packages/framework.yaml

@@ -7,7 +7,8 @@ framework:
     # Enables session support. Note that the session will ONLY be started if you read or write from it.
     # Remove or comment this section to explicitly disable session support.
     session:
-        handler_id: null
+        handler_id: 'session.handler.native_file'
+        save_path: '%kernel.project_dir%/var/sessions/%kernel.environment%'
         cookie_secure: auto
         cookie_samesite: lax