Gemini 2.5 got into as close to a heated argument with me as possible about the existence of a function in the kotlin coroutines library that was never part of the library (but does exist as a 5 year old PR still visible in github that was never merged in).

It initially suggested I use the function as part of a solution, suggesting it was part of the base library and could be imported as such. When I told it that function didn't exist within the library it got obstinate and argued back and forth with me to the point where it told me it couldn't help me with that issue anymore but would love to help me with other things. It was surprisingly insistent that I must be importing the wrong library version or doing something else wrong.

When I got rid of that chat's context and asked it about the existence of that function more directly without the LLM first suggesting its use to me, it replied correctly that the function doesn't exist in the library but the concept being easy to implement... the joys(?) of using an LLM and having it go in wildly different directions depending upon the starting point.

I'm used to the opposite situation where an LLM will slide into sycophantic agreeable hallucinations so it was in a way kind of refreshing for Gemini to not do this, but on the other hand for it to be so confidently and provably wrong (while also standing its ground on its wrongness) got me unreasonably pissed off at it in a way that I don't experience when an LLM is wrong in the other direction.