Python: Autonomous handoff re-invokes downstream orchestrations (Magentic/Concurrent) and can fail with already completed runtime error

[BharathRajR]

When using HandoffBuilder in autonomous mode as a non-terminal orchestration and chaining it to another orchestration, I see repeated downstream invocations.

Observed behavior

• In handoff + magentic, downstream gets invoked multiple times.
• In handoff + concurrent, I see multiple agent_started events, suggesting repeated invocations.
• This appears to happen because autonomous handoff emits multiple outputs, and downstream gets triggered for each output.

Exact error seen (handoff + magentic)

• Workflow execution failed: RuntimeError: This Magentic workflow has already been completed. No further messages can be processed. Use the builder to create a new workflow instance to handle additional tasks.

Expected behaviour or clarification needed

• Please confirm whether this is expected by design for autonomous handoff when chained to downstream orchestrations.
• If expected, please share the recommended composition pattern so downstream executes once per logical handoff completion.
• If not expected, please confirm if this should be treated as a bug.
• Clarification on whether the turn limit should be 50 for it to work in autonomous mode, if not how to set a valid turn limit