In modern software engineering, efficient release engineering workflows are essential for quickly delivering new features to production. This not only improves company productivity but also provides customers with frequent updates, which can lead to increased profits. At Microsoft, we collaborated with the Identity and Network Access (IDNA) team to automate their release engineering workflows. They use differential testing to classify differences between test and production environments, which helps them assess how new changes perform with real-world traffic before pushing updates to production. This process enhances resiliency and ensures robust changes to the system. However, on-call engineers (OCEs) must manually label hundreds or thousands of behavior differences, which is time-consuming. In this work, we present a method leveraging Large Language Models (LLMs) to automate the classification of these differences, which saves OCEs a significant amount time. Our experiments demonstrate that LLMs are effective classifiers for automating the task of behavior difference classification, which can lead to speeding up release workflows, and improved OCE productivity.