[BUG] Scheduled routine silently skips execution — "next run" advances without firing

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

A Claude Code routine set to run on a recurring hourly schedule consistently skips scheduled executions. The scheduler correctly detects when a scheduled time has passed and advances the "next run" timestamp to the following interval, but the routine itself never executes.

The scheduled time passes silently. The "next run" timestamp advances to the next interval (confirming the scheduler is aware the time passed), but no execution occurs. This has happened on 4+ consecutive scheduled intervals.

Manual runs work fine.

What Should Happen?

The routine should fire at the scheduled time and appear as a "Scheduled" entry in the Runs list.

Error Messages/Logs

Steps to Reproduce

1. Create a routine with an hourly schedule (every hour, at :00 minutes)
2. Wait for the next scheduled run time to pass
3. Observe that "next run" advances to the following hour, but no run appears in the Runs list

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.97 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

I'm using a Windows on Arm machine. However, this routine was set up on claude.ai/code/routines so the OS should have had no bearing on the behavior of the routine.

<img width="1789" height="358" alt="Image" src="https://github.com/user-attachments/assets/7478acaa-ea9f-492c-a854-320554536c01" />

As visible in the image, the only run that occurred was a manual one in spite of the scheduled time having passed.