The POCO team is aware of the new bug in the pubg where the icons and buttons of the pubg game are hidden under the notch. The bug is being addressed and the POCO team reached out to the PUBG developers to fix this issue.

Official news from the poco team - http://en.miui.com/thread-3854103-1-1.html

Note - I will update this once the issue is fixed. So please do follow.