Dev's SEC filing bot silently skipped all foreign firms due to wrong form section lookup

A software developer building a US-listed company analysis bot discovered it was silently skipping risk-factor data for all foreign firms without throwing any errors. The bug stemmed from the bot always searching for 'Item 1A' — the risk section in the US Form 10-K — while foreign companies listed in the US file a Form 20-F, which places risk factors under 'Item 3.D' instead. Because the missing section was caught and returned as an empty string, the downstream LLM interpreted the absence of data as a clean bill of health, producing false 'no risk factors' results. The fix involved branching logic to select the correct section ID based on form type, and updating the extraction method to return None on failure rather than an empty string, making errors distinguishable from genuinely empty data. The developer noted two key lessons: domain knowledge of the data being processed is as critical as coding skill, and silently swallowing errors by defaulting to empty values can cause dangerous, hard-to-detect data loss.