form suddenly disappeared

At first, everything was fine, but after I entered the data into the form there were some inputs that were missing. When the application is closed and reopened, the form runs normally. Someone can help me please ?

I use ionic 3.9.2 and cordova 9.0.0 (cordova-lib@9.0.1), and this is my ionic info:

cli packages: (/usr/local/lib/node_modules)

@ionic/cli-utils  : 1.9.2
ionic (Ionic CLI) : 3.9.2

global packages:

Cordova CLI : 9.0.0 (cordova-lib@9.0.1) 

local packages:

@ionic/app-scripts : 3.1.0
Cordova Platforms  : android 8.1.0
Ionic Framework    : ionic-angular 3.9.2

System:

Node : v8.10.0
npm  : 3.5.2 
OS   : Linux 5.0