Root cause: race condition between setActiveChatId and the persist
effect. When switching from session A to B, setActiveChatId(B) triggers
the persist effect which writes {chatId: B, questions: [A's data]} to
sessionStorage BEFORE the async selectChat clears the task lane. The
sessionStorage fallback then finds chatId === B and restores A's stale
task lane data.
Fix: clear task lane state synchronously in selectChat before the await.
Server-side pending_task_lane restores it if the new session has data.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
b03f84aecf