Double Bluesky Post Exposes Race Condition in Multi-Machine CI Publishing Setup

On August 31, 2026, a developer publishing pipeline posted the same announcement twice on Bluesky after two separate machines ran the same CLI 57 minutes apart, both passing duplicate checks. The root cause was an idempotency key stored in a git-tracked file that was not pushed to the remote repository until after the second machine had already read the unupdated state. An immediate fix moved duplicate checks off local files and onto live platform data, querying Bluesky and dev.to directly before each write. However, engineers acknowledged this still leaves a narrow race-condition window where two simultaneous runs could both read a clean feed and both post. A second fix, shipped six days later, eliminated the problem structurally by decommissioning the redundant machine, ensuring only a single writer could exist at any time.