I have attcahed videos to demonstrate the issue. Please see the video and note, keyboard pops up when sign up button is clicked in Android and due to this the modal is cut from top as it is pushed up, and in IOS this phenomenon does not happen.
https://global.discourse-cdn.com/meta/original/3X/0/2/02bc90197225efc955983dd207f2355950ef8fc1.mp4 https://global.discourse-cdn.com/meta/original/3X/f/f/ffd78049366d326496e85543d64efe7cec189d7f.mp4
I hope the video is clear.