Flickering sidebar when scrolling page [closed]

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  1. You would need to know since when / which change it starts flickering. // you said since the content change. So try to change back step by step until you know which content component exactly causes this.

  2. Debug that change which caused that flickering.

There are playing a lot of factors in here: Theme, Theme CSS, Custom CSS, Theme JS, Widgets CSS and JS (maybe from another Plugin?) which make that unpredictable to give a correct answer. So just guessing.