I think what we sense as “LLM design” now is what used to be “oh, they used a popular squarespace template or Wordpress theme”. Makes sense that as the models were training on UI, they would heavily favor recurring patterns such as re-used design templates and popular UI libraries over the bespoke stuff.

That plus the AI generated imagery being used in hero images on a lot of sites is built from lazy prompts and riddled with tells like weird shape choices, smooth glossy surfaces, or mangled text.