In late August, a bug affecting the resolution of Feature Flags using the JS SDK in recent Chrome versions emerged, causing unexpected default values to appear without any code changes on the affected platform. The issue was traced back to a map lookup problem in the js-sha256 library, which had not been updated in years. This bug, reported by users and confirmed through reproducible code on GitHub, was due to a recent Chrome JIT compiler optimization error that incorrectly handled a specific variable. The mitigation involved using the problematic variable in a closure to prevent its premature optimization, and a patch for the JS SDK was released on August 27 to address the issue. Additionally, the text discusses the use of CUPED for faster, less biased experiments and highlights insights from Ronny Kohavi and Allon Korem on experimentation culture and infrastructure. It also touches on the evolution of the web experience platform Optimizely, shifts in Facebook's product strategies due to A/B testing, and the unique culture at Statsig, emphasizing the reliability of A/B testing for gathering evidence.