hallucination

xAI's Grok 4.20 scores 48 on Artificial Analysis' Intelligence Index—6 points ahead of Grok 4 but trailing Gemini 3.1 Pro Preview and GPT-5.4 at 57. The model distinguishes itself with a 78% non-hallucination rate on the AA Omniscience test, the highest recorded across any model tested.

Apple Intelligence, which automatically summarizes notifications and messages on hundreds of millions of devices, systematically generates stereotyped and hallucinated content according to an independent AI Forensics investigation. The analysis of over 10,000 AI-generated summaries reveals bias baked into the feature that pushes problematic assumptions to users unprompted.