A question on the preservation of the Quran

So in [Sahih al Bukhari 6829](https://sunnah.com/bukhari:6829) , we get to know that the verse of stoning was not there in the Quran. Doesn’t that mean that the Quran is not preserved? Or is it that the verse was not meant to be in the Quran at the first place but the ruling was supposed to be there?