Issue with ion-radio-group with ngModel ionic 4

I am using ion-radio-group with ngModel with hide/show functionality. Below is my UI code for view.

<ion-button (click)="showSection()" size="small" >show</ion-button>
<ion-button (click)="hideSection()" size="small" >show</ion-button>

<ion-list style="margin-bottom: 0px;" *ngIf="show">
  <ion-radio-group [(ngModel)]="payment.paytype">
      Select Payment Method

  <ion-radio value="online"></ion-radio>

      <ion-radio value="token"></ion-radio>

This is my hide/show code on controller.


async showSection()
{ = true;
async hideSection()
{ = false;

Issue came when i select radio and performing hide show operation. My UI get freezes. Please help me to solve this issue. Your help would be appreciated. Thanks in Advance. I am using Ionic 4.

Note: - If i am not selecting radio and doing hide/show no issue is coming. Issue is coming only when i selected the radio and then hide/show.