In-process teammate/subagent completion notifications frequently delayed by tens of minutes, require manual nudge

Description

When dispatching subagents via the Agent tool within a single Claude Code session (in_process_teammate tasks), completion/idle notifications for those subagents are frequently delayed by 30-40+ minutes, even for small, fast tasks (e.g. reviewing a ~10KB diff). The subagent has actually finished and gone idle well before its notification reaches the dispatching session.

Correction to a previous report (#87001, closed): I initially misattributed this to "another Claude session relaying a message," based on the generic "this came from another Claude session" wording that also appears on in-process teammate notifications. ps -ef confirmed only one claude process was running, and TaskStop confirmed the subagents were in_process_teammate tasks in the same session — so this is not a cross-session issue. The actual, reproducible symptom is: idle/completion notifications for in-process subagents are unreliable/delayed, and the user reports this happens frequently ("all day long"), not as an isolated incident.

Reproduction pattern

1. Dispatch a subagent (Agent tool, general-purpose or similar) for a bounded task.
2. Subagent completes and goes idle in a few minutes.
3. The dispatching session receives no timely notification — waiting 30-40+ minutes produces nothing.
4. Sending an explicit message to the named subagent (asking "are you done?") is what actually elicits its report — the notification alone does not reliably surface it in time.

Impact

• Forces manual polling/nudging workarounds, defeating the purpose of async subagent dispatch.
• Makes multi-agent orchestration workflows (e.g. plan-and-review loops) far slower than necessary, since each step effectively requires manual intervention to unstick.

Environment

• Claude Code CLI, Agent tool / in-process teammate subagents, single session
• OS: Linux (Fedora 7.1.8-200.fc44.x86_64)
• Reported as a recurring, frequent occurrence, not a one-off

Expected behavior

Completion/idle notifications for in-process teammate subagents should reach the dispatching session promptly (within a small multiple of the subagent's actual runtime), without requiring a manual check-in message to elicit the response.