It's not possible to hide the initial tooltip on bar charts.

[IbrH]

I tried every possible options that is supposed to hide the initial tooltip before the image is created, but none work. My example code:

var chartNode = new ChartjsNode(550, 400);
  data = {
  datasets:[{
    data:[65,59,80,81,56,55,40],
    fill:false,
    backgroundColor:["rgba(255, 99, 132, 0.2)","rgba(255, 159, 64, 0.2)","rgba(255, 205, 86, 0.2)","rgba(75, 192, 192, 0.2)","rgba(54, 162, 235, 0.2)","rgba(153, 102, 255, 0.2)","rgba(201, 203, 207, 0.2)"],
    borderColor:["rgb(255, 99, 132)","rgb(255, 159, 64)","rgb(255, 205, 86)","rgb(75, 192, 192)","rgb(54, 162, 235)","rgb(153, 102, 255)","rgb(201, 203, 207)"],
    borderWidth:1}]
  };
  var options = {
    type: 'bar',
    data: data,
    options: {
      title:{
        display: true,
        text: "Members in each category"
      },
      tooltips: {
        enabled: false,
        custom : function(tooltipModel){
          tooltipModel.opacity = 0;
        }
      },
      legend: {
        labels: {
          //fontColor: 'white',
          //fontSize: 18
        }
      },
      scales: {
        xAxes: [{
          gridLines: {
            color: 'rgba(255,255,255,0.1)'
          },
          type: 'category',
          labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
          ticks: {
            fontSize: 15,
            fontColor: 'white'
          }
        }],
        yAxes: [{
          gridLines: {
            color: 'rgba(255,255,255,0.1)'
          },
          ticks: {
            fontSize: 15,
            fontColor: 'white'
          }
        }]
      }
    }
  };
  await chartNode.on('beforeDraw', function (Chartjs) {
    Chartjs.defaults.global.showTooltips = false;
    Chartjs.defaults.global.tooltips.enabled = false;
  });
  await chartNode.drawChart(options);
  buffer = await chartNode.getImageBuffer('image/png');

[IbrH]

I realized it's not a tooltip but just a box and label.