Why do you think Bing Chat is going in a slightly different direction and not using this format exactly?

Their prompt - https://old.reddit.com/r/bing/comments/11bd91j/release_of_th...

Wouldn't it be better to unify around ChatML, for the sake of all future training data being consistent? I thought it was strange that they used <|im_start|> but not the rest of the ChatML syntax.

(There is always the possibility that they are using it, but the AI has hallucinated a slightly different syntax when repeating it)