i find it hard to believe no one maintaining these 'material.io' pages doesn't notice the animated sticky header [0] popping in and out again and again and again as you scroll down the page. [0] https://i.imgur.com/HPLI85T.gif
Scrolling up gets it to pop out for me, but I need to scroll up a lot more than you do in order to replicate this (scrolling down normally looks fine on Linux/Chrome). Sounds like it might be possible they haven't noticed it and would appreciate a bug report. :)