Failed Google interview experience

I had my first round of the interview and I’m confused about the feedback. Apparently, I have strong coding skills, handled edge cases very well and was able to clearly clarify requirements and explain my thinking well. However, they are not proceeding because “you missed creating a class to keep track of the state and update it”. Wtf? I did create the class and kept the state and every thing and to be honest, there was a moment where, after I explained my thinking on how to solve the problems (had three different problems to solve — two of them pretty straightforward and the third with a trick) and got a nod from the interviewer to proceed with the plan, the interviewer jumped at me and said: “You need to create a class.” I thought that was so obvious that I just replied: “Yep, of course” and proceeded with coding which consisted of a class among other things.. To make it even harder, the interviewer did not paste the question at all in the docs! I just got three method signatures in pseudo-code (along with an extremely simple example for the third tricky question) and had to figure it out on my own as the interviewer was explaining the problem!!! The behavioral interview went great and I got a ‘strong’ result and Google is “looking for people like me”. What does one make out of such feedback?