Why did ChatGPT4o behaved in this way. I could have easily trusted it if I was in a rush. Bug? Please solve this

I don’t need to say much if you look at the provided screenshot. What scares me is this is premium version and I could have easily overlooked it if I was in rush of getting the answer and using it somewhere. And I am also thinking how many times in the past this must have happened with me. I could understand if it was a very difficult or analytical question, which chatgpt4o is (assumed to be) greatly capable of, but this feels really wrong. Help.