iPhone 13 Pro Max keyboard flickering

So i bought a iphone 13 pro max, i was very happy to finally get it but there is problem with keyboard. When i type in at Whatsapp or at a random app i installed from App Store, the keyboard flickers 0,5 millisecond and it makes me unconfortable. So my question is, is this a problem caused by the new ios 15.01 or a problem with the new iphone 13 series?

[Re-Titled by Moderator]