A study shows that on March 4, 2026 when GPT-5.3 instant became ChatGPT's default model, overnight 20% fewer domains were cited in responses:

• Avg # of unique domains per response fell from 19 to 15
• Avg # of unique URLs per response fell from 24 to 19

Good to remember that LLM/AI search evolves all the time, so changes you notice in your site's citation visibility could very well have *nothing* to do with your SEO/AEO/GEO efforts.