iOS Scrolls Down When App Is Opened

I’ve only just noticed this…

I thought this was initially something wrong with my Webflow sites, but it happens to all sites I visit.

Open a website in iOS Safari (I’m using an iPhone 11).
Close Safari.
Re-open Safari.

The whole website seems to then scroll down 50px or so…

What’s the idea behind this and why is Safari doing this?

If you do this repeatedly you end up scrolling to the very bottom of the page just by opening and closing Safari!