[Bug] Auto-interrupt regression in plan mode and heavy operations (2.1.78+)

Bug Description
[Follow-up] Auto-interrupt regression persists from 2.1.78 through 2.1.80

Previously reported this via /bug on 2.1.78. The issue remains unresolved as of
2.1.80.

Symptom: After triggering plan mode or any heavy operation (subagent, Explore
agent, large file reads), the session enters an "Interrupted" state automatically —
without pressing Escape or any user intervention. Once interrupted, ALL subsequent
prompts in that session are immediately interrupted as well. The session becomes
completely unusable.

Reproduction steps:

1. Install claude-code 2.1.78 or later (tested up to 2.1.80)
2. Start a session and enter plan mode, or trigger a subagent/Explore call
3. Session auto-interrupts within seconds
4. Any follow-up prompt also gets interrupted immediately

Workaround: Downgrading to stable (2.1.62) completely resolves the issue.

Environment: Linux, CLI terminal
Related GitHub issues: #35643, #36143, #23350

This has been broken for 3+ versions now. The npm stable tag is still pinned at
2.1.62, which suggests awareness of regressions, but there's been no visible
progress on this specific bug.

Environment Info

• Platform: linux
• Terminal: vscode
• Version: 2.1.80
• Feedback ID: 6ff00bc8-ed92-4443-9756-4bcbb53843f4

Errors

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