Silent retry bug left automated trading positions unprotected despite passing all health checks

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A developer running an automated paper-trading system discovered that its self-healing recovery routine had been silently failing for hours, leaving open positions without stop-loss protection. The bug stemmed from a deterministic client order ID generated by appending a fixed suffix to an existing identifier, which the broker rejected on every retry after the first attempt because the ID was no longer unique. Every individual component of the recovery chain was logically correct in isolation, yet the combined retry sequence permanently failed without raising any alerts. A 55-point health check passed throughout the entire incident because it verified structural integrity — whether processes were running and files were loaded — but not logical correctness, such as whether broker responses matched expected outcomes. The issue was ultimately uncovered not through code review but by manually running a sync command and reading the raw error returned by the broker.

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