"Up until the semi finals, it seemed like nothing would be able to stop Grok 4 on its way to winning the event," Pedro Pinhata, a writer for Chess.com, said in its coverage. "Despite a few moments of weakness, X's AI seemed to be by far the strongest chess player... But the illusion fell through on the last day of the tournament." He said Grok's "unrecognizable" and "blundering" play enabled o3 to claim a succession of "convincing wins".

I think the main takeaway is that these models are fundamentally inconsistent, and you can never assume they’re going to be reliable based on past performance.