I’m sorry, the error was in the function that calls the POST service, in it I was mistakenly changing the value of productos, I just deleted that line and everything started working fine

I have a list in Angularjs that is automatically filled with *ngFor, but when I make use of a POST service, said list stops working and only shows the default option

<select id="descripSel" (change)="selectDescrip()" >
  <option >Selecciona un producto</option>
  <option *ngFor="let item of productos | filter : txtdescrip : 'descripcion'" value="{{item.descripcion}}">{{item.descripcion}}  </option>
</select>

The function in the component.ts is this one, it uses a POST service and saves some values, but then my list stops working:

  selectDescrip() {
      this.seldescrip=<HTMLSelectElement>document.getElementById("descripSel");
      this.descripcion=this.seldescrip.value;
      var j_number=null;
      for(var i=0;i<this.productos.length;i++) {
        if(this.productos[i]["descripcion"]==this.descripcion) {
          j=i;
        }
      }
      console.log(j)
      this._serviceProductos.postDescrip(this.productos[j])
        .then(response=>{
          if(response["producto"]==null||response==null){
            alert("No se encontró ningún producto con la descripción especificada, favor de validar la descripción")
          } else {
            this.productos=response.productos;
          this.resprod=response["producto"];
          this.precios=[
            this.resprod["precio_contado"],
            this.resprod["precPG_99"],
            this.resprod["precPG100_399"],
            this.resprod["precPG400"],
            this.resprod["precArq_99"],
            this.resprod["precArq100_399"],
            this.resprod["precArq400"],
            this.resprod["precSubD_A"],
            this.resprod["precSubD_B"],
            this.resprod["precSubD_CD"]
          ]
          this.descripcion=this.resprod["descripcion"];
          this.sku=this.resprod["sku"];
          this.actualizarFoto(this.resprod["foto"]);
          console.log(this.resprod)
          }
        })
        .catch(error=>{
          console.log(error);
        })
  }