iOS: wrong page layout after switching from portrait to landscape orientation and back

Bug Reports
1

Just tried SN web-app on iOS (iPhone 6s, iOS 14, Safari).
There is a wrong layout after switching from portrait to landscape orientation and back (header and footer are cropped):

SN_iOS
SN_iOS750×1334 134 KB

Here is the video.

2

Further investigations: looks like SN thinks, that the address bar is removed (when it is actually not): see another video.

3

It is exactly the same issue, as described here. Reproducible both on iOS and iPadOS.