I don’t think it’ll cause bounce on mobile because we use fixed position when scrolling and absolute positioning when it docks, so it’s never influencing the layout anyway.
I did a quick test where I just hide it with css when it gets the docked class (because that’s why the positioning jumps when loading; the page is short and the progress bar docks)… no bounce when it disappears/reappears
The other option is to undock it and keep it in a fixed position while loading, but the problem with that is if you’re jumping up to the top of the page from all the way at the bottom (like when you’re at suggested topics)… I think you’d see a position jump when the timeline goes from docked to a fixed position?
Anyway, I’ll try it out and see what works best.