When calling an agent which has tools and an output schema, the invocation_id is not being set on the final model response event. This prevents the agent from running on Agent Engine where invocation_id is required on all events.

To Reproduce

• Create an Agent with tools and an output schema defined
• Run the agent
• Review the events in ADK web, the event titled functionResponse:set_model_response has an invocation_id
• The event after this does not have an invocation_id set.

Expected behaviour
All the events should have an invocation_id

ADK Version
1.11.0

Model
gemini-2.5-pro

Additional context
I believe the bug lies here as only the author is being set on the event and not the invocation_id.

Running on Agent Engine results in this error:

"google.genai.errors.ClientError: 400 INVALID_ARGUMENT. {'error': {'code': 400, 'message': 'List of found errors:\t1.Field: event.invocation_id; Message: Required field is not set.\t', 'status': 'INVALID_ARGUMENT', 'details': [{'@type': 'type.googleapis.com/google.rpc.BadRequest', 'fieldViolations': [{'field': 'event.invocation_id', 'description': 'Required field is not set.'}]}]}}