>is "you are absolutely right" wrong somehow?

It makes sense in English, however:

a) "you are" vs "you're". "you are" sounds too formal/authoritative in informal speech, and depending on tone, patronising.

b) one could say "you're absolutely right", but the "absolutely" is too dramatic/stressed for simple corrections (an example of sycophancy in LLMs)

If the prompt was something like "You did not include $VAR in func()", then a response like "You're right! Let me fix that.." would be more natural.

Thanks for the thorough explanation, that, indeed, is a level of nuance that's hard for me to spot.

Interestingly, "absolutely right" is very common in German: "du hast natürlich absolut Recht" is something which I can easily imagine a friend's voice (or my voice) say at a dinner table. It's "du hast Recht" that sounds a little bit too formal and strong x[.

Agreed on the sycophancy point, in Gemini I even have a preamble that basically says "don't be a sycophant". It still doesn't always work.