yes, and i find it disturbing. either a feature is there, then it should be visible at all times, or it should be off completely. while i am reading my eyes are tracking the locations of those buttons/links so that i can quickly move the mouse to use them. if they are hidden that slows me down and gets in the way. it makes sense on small screen like mobile where it is better to use the space to show more content and have actions hidden behind a menu, but not on the desktop.