Hi apuente,
Thanks for the live sample and the .rp file. As it turns out, this is a known issue we have on file where the “Pin to Browser” feature doesn’t work on iOS devices when the HTML Sidebar is either opened or minimized, and I’ve added a note to the current bug report to let our QA team know you’re running into this issue as well.
As a workaround in the meantime, you’ll want to either view the prototype with the HTML Sidebar completely closed or view the prototype on an Android device.
Hopefully this helps a bit!