highcharts-chart error series undefined, but the chart is visible

I am making a project in angular (7) and when I put the highchart graphs (highcharts-chart module), it throws me the following error on the console:

ERROR TypeError: Cannot read property 'series' of undefined

The strange thing is that the graph is displayed well, but I think that I am either passing the variables wrong, or initialized badly or something like that, therefore, even if it is seen, I would like to leave it without console errors.

The code I have is the following.

TemplateHTML

<highcharts-chart [Highcharts]="Highcharts" [options]="graficoOptions"></highcharts-chart>

Controller

this._contratosService.getEstados(localStorage.getItem('idCliente')).subscribe(
        async data => {
          this.graficoOptions= this._funcionesService.decodificarToken(data);
          for (let i = 0; i < this.arraySituaciones.length; i++) {
            this.array = this.array.concat([
              {
                name: this.arraySituaciones[i],
                y: this.arrayContadorContratos[i],
                selected: false
              }
            ]);
          }

          this.options = JSON.parse(this._GraficosService.graficosOption);
          this.graficoOptions= {
            lang: this.options,
            chart: { type: 'line' },
            exporting: {
              buttons: {
                contextButton: {
                  menuItems: [
                    'printChart',
                    'separator',
                    'downloadPNG',
                    'downloadJPEG',
                    'downloadPDF',
                    'downloadSVG',
                    'separator',
                    'downloadCSV',
                    'downloadXLS'
                  ]
                }
              }

            },
            title: { text: 'Estados de los contratos' },
            subtitle: {
              text:
                'Se muestran la cantidad de contratos que existen en cada estado.'
            },
            tooltip: {
              pointFormat:
                '<span style="color:{series.color}">Contratos: </span>: <b>{point.y}</b><br/>',
              shared: true
            },
            series: [
              {
                type: 'pie',
                allowPointSelect: true,
                keys: ['name', 'y', 'selected', 'sliced'],
                data: this.array,
                showInLegend: true
              }
            ],
            plotOptions: {
              series: {
                cursor: 'pointer',
                events: {
                  click: function(e) {
                    console.log('1234');
                  }
                }
              }
            },
            credits: { enabled: false }
          };
        });