Earlier quoted context omitted.
" but the interview engine is already running at full speed:" I dont know if this is a recent thing, but I had a similar thing where an interviewer was racing forward, and would only accept the answers he had in mind. In Python, he asked me how to search for substring. I was thinking but he started hurrying me. So I said regex and started writing a regex. "No, there is an inbuilt method" I couldnt remember the method…
He was being rude, but I'm equally baffled by your description. It was very weird that you couldn't figure out which method is to search for substring when you have access to google search. And it was triply weird that when he already said he wanted the non-regex way and you insisted on that.
That said, really... finding a trivial python function using google search, that is a real life work skill. It's 100% real and not made up for interviews. I guess these days one would ask the LLM, too. The only artificial thing was the time pressure which, granted, complicates things needlessly, but other than that, the fact the candidate didn't come up with an answer is still a red flag. (I wouldn't disqualify them just for this, but maybe there were other red flags already?).