Riot Games Senior Software Developer interview questions

London based. HR phone screen followed by HM "cultrual fit" interview, where the HM showed up without much enthusiam, which is quite odd compared to other interview experience. Typical "tell me a time" questions but they wanted to dig deeper. I demonstrated the "riot values" in my answers "by the book" but I was told to be a "non culture fit". It's a black box how these ratings are decided.