AgentEngine async_stream_query not working as expected. Only returns first few events. #3003

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Describe the bug
I'm trying to invoke the AgentEngine using vertexAI sdk for python. My root agent calls multiple agents in sequence. When I invoke async_stream_query passing the input, it returns only the first 3 events out of 27 events.

To Reproduce
agent = agent_engines.get("projects/PROJECT_ID/locations/LOCATION/reasoningEngines/RESOURCE_ID")

async for response in agent.async_stream_query(
input="case_id"
):
print(response)

Expected behavior
This method should return all events asynchronously

Desktop (please complete the following information):

• OS:
• Python version(python -V): 3.12.5
• ADK version(pip show google-adk):1.13.0

Model Information:

• Are you using LiteLLM: No
• Which model is being used: gemini-2.5-pro