3 Duplicate Instagram Posts in 8 Hours: Anatomy of a False-Negative Success Check

Description and use

An automated Instagram posting script duplicated a carousel post three times due to a false-negative verification. Implementing text normalization, API-first verification, and a fail‑closed design resolved the issue.

Problem

Automated Instagram posting script repeatedly posted the same carousel three times due to a false-negative verification that misidentified a successful post as a failure.

Outcome

The fixes eliminated duplicate posts by normalizing text, prioritizing API verification, and adopting a fail-closed strategy, ensuring accurate success detection and preventing unnecessary retries.

Workflow

• Generate caption and post carousel via IG API
• Run _verify_landed() to compare first 12 chars of caption with DOM inner_text
• If ok:false, scheduler retries next slot
• If verification fails repeatedly, duplicate posts occur

Evidence

_verify_landed() fetched the profile page DOM and compared the first 12 characters of the body text with the first 12 characters of the caption.

Source

The fix, in three parts: 1. Caption normalization, 2. API-first lookup, 3. Fail-closed design.

Source