Fading fields in ionic after selecting a select option

I'm implementing a feature where the user selects a select option and is sent to a function that adds to my model.

For some reason, after selecting the option of my select , the next field of my ngfor adds up, it reappears if I click on it, everything works normal in the ionic serve, but when I roll the pro build cell, after selecting the select the field of the other index some.

My code:

resposta: string[] = [""];
saudacao: string = '';


<div>

      <ion-row>
        <div class="col-8">
        <ion-item>
          <ion-textarea name="resposta{{i}}" [(ngModel)]="resposta[pergunta.id]" value="{{resposta[pergunta.id]}}" placeholder="Resposta" clearInput></ion-textarea>
        </ion-item>
        </div>
      <div class="col-4">
          <a (click)="respondePergunta(i)"><ion-icon class="responderperguntaicon" name="ios-arrow-dropright-circle"></ion-icon></a>
          <a (click)="presentActionSheet()"><ion-icon id="maisopcoes" color="primary" name="more"></ion-icon></a>
      </div>
      </ion-row>

    <ion-item>
      <ion-label>Resposta Automática</ion-label>
      <ion-select (ionChange)="adicionaArrayRespostaAutomatica($event, pergunta.id)">
        <ion-option value="Sim, temos no estoque ">Sim, temos no estoque</ion-option>
        <ion-option value="Não, não temos no momento ">Não, não temos no momento</ion-option>
      </ion-select>
    </ion-item>

    <ion-item>
      <ion-label>Inserção Rápida Sistema</ion-label>
      <ion-select (ionChange)="adicionaArrayInsercaoRapida($event, pergunta.id)">
        <ion-option value="{{saudacao}}">Saudação</ion-option>
      </ion-select>
    </ion-item>

  </div>

My role:

adicionaArrayRespostaAutomatica(event, index){
  if(this.resposta[index] == null){
    this.resposta[index] = '';
    this.resposta[index] = this.resposta[index] + ' ' + event;
  }else{
  this.resposta[index] = this.resposta[index] + ' ' + event;
  }
}

adicionaArrayInsercaoRapida(event,index){
  if(this.resposta[index] == null){
    this.resposta[index] = '';
    this.resposta[index] = this.resposta[index] + ' ' + event;
  }else{
  this.resposta[index] = event + this.resposta[index];
  }
}