Desktop (Windows): one-time scheduled task runs twice on catch-up after the PC was off

Environment: Claude desktop app 2.19675.0.0, Windows 11 Home 10.0.26200, Code tab, local scheduled task.

What happened: A one-time scheduled task was set for 2026-10-04 10:07 local time. The PC was powered off at that time and cold-booted at 10:25:58. After the app started, the missed run caught up, but it started two sessions for the same task:

• run 1 started 2026-10-04T08:32:41Z
• run 2 started 2026-10-04T08:32:58Z (17 seconds later)

list_task_runs for the task reports totalRuns: 2. Both sessions received the identical scheduled-task prompt and ran the task in full, in parallel.

Expected: A missed one-time task runs once on catch-up.

Impact: Any task with side effects (notifications, file writes, git commits, messages) does them twice. Here, both runs wrote to the same files, and both attempted to send the same notification.

Repro (likely): Create a one-time local scheduled task, power the PC off before its time, boot after its time, open the desktop app, check the task's Runs list.