[BUG] 2.1.214 macOS: orchestrator session .jsonl deleted while <UUID>/subagents/ preserved — appears to reproduce #60368 (not retention)

Preflight

• Latest version: 2.1.214
• Related (same signature, CLOSED): #60368 · possibly related: #70632, #59248

What's wrong

On 2.1.214 (macOS), several sessions that spawned subagents (Task / orchestrated sub-agent flow) lost their parent (orchestrator) transcript ~/.claude/projects/<slug>/<UUID>.jsonl, while the companion directory ~/.claude/projects/<slug>/<UUID>/ — containing subagents/ and/or tool-results/ — was fully preserved.

This is exactly the signature described in #60368 ("background-fleet deleteJob silently unlinks main session JSONL, companion dir preserved"), which is CLOSED — so this looks like an incomplete fix or a regression on 2.1.214.

Evidence (filesystem forensics)

• Only subagent / heavy-tool sessions are affected. Plain conversational sessions on the same machine survived an identical kill -9 / SIGKILL with their .jsonl intact — and those never create a <UUID>/ subfolder at all.
• Affected sessions: 4 orphaned <UUID>/ dirs — one with only tool-results/, three with only subagents/. No <UUID>.jsonl for any of them, and none present under any other project slug.
• Not retention / TTL: affected files were 1–3 days old; no cleanupPeriodDays configured (default 30). The #60368 reporter saw the same with cleanupPeriodDays: 36500.
• Not a post-exit deletion: the affected project directory's mtime is earlier than the session's last activity — i.e. no .jsonl was deleted from that dir after the session ran. Consistent with the transcript never being persisted there (cf. deferred-write #70632).
• No .jsonl.tmp / .bak remnants; disk 61% used.

Expected

The orchestrator / parent .jsonl should never be unlinked while its <UUID>/subagents/ data is retained. Subagent-spawning sessions should persist the parent transcript at least as reliably as plain sessions.

Environment

• Claude Code: 2.1.214
• OS: macOS 15.7.7 (build 24G720), Darwin 24.6.0
• Sessions launched from a standard terminal (not the VS Code integrated terminal).