black sreen before loading. Instant Apps

Greetings!We have a problem with instant app. When you download the game https://play.google.com/store/apps/details?id=com.oriplaygames.cutiepaws&hl=en a black screen for about 10 seconds and only then is the download of our game, what could be the reason? I want to understand what is happening at this moment of the black screen, is it downloading the apk or what is happening, how can I fix this? Is it possible to replace this black area with some kind of inscription? apk size about 9.25 MB. Used settings for optimization from documentation and assetbundle, the project on Unity.
They also used the plugin for Unity instant app, and did it manually.
video

https://drive.google.com/file/d/1c5oMXizgT_Y9UFYUyYvaKVsqWOnLr0CS/view?usp=sharing