Scrolling in a PWA hangs on iOS safari

Whenever I touch the bottom-browser bar on iOS-Safari, any PWA app hangs.
Has anyone seen this?

reproduce:

  1. choose conference app on pwa.ionic.io (or any other)
  2. scroll to top or bottom of the list
  3. touch the safari bottom bar
    09

Scroll hangs for many seconds.

No issue on a Mac or any other browser. Since this happens also to my PWA, I am looking for a solution.