Unknown bug in app

Hey guys,i have one tournament application. In that,there is a bug. Suppose if i open app first time,it works fine. But if i open app again,then data isnt showing. Everything gets blank. Many components are becomes invisible. I will drop apk here. Please install apk,open and register first. Then use it for few seconds, then remove from background and then open it again. There you will find a bug. Please give me a solution. Thanks.
Apk link:War Dogs_1.0.apk - Google Диск

Signup button not found
Android OS: 8.1

I think the problem is in screen initialize.
Show your blocks or AIA if possible.

I will send aia for you only

I found two errors even without entering in your app.
First one is on Login screen and second is on register screen.
Background is showing white originally.But when it gets focus its background changes and label and buttons are visible.
Also I am not able to see register button as ‘reported’ by @asimjib93

Not only this one,several problems are there

can i share aia file?

Sharing Aia could be helpful.