I'm working on an AI Data Analyst in MLJAR Studio and found this small but interesting bug while testing a medical data use case. The AI-generated Pandas code looked correct and executed without errors, but the dataframe was misaligned. The first patient had 148 pregnancies because glucose values were shifted into the Pregnancies column. The interesting part for me was that the bug was caught only because both the displayed dataframe and an extra LLM output checking step were reviewed.