multipleXYLineChart doesn't seem to flush values when calling load()

[songololo]

I am using a line graph to display a multipleXYLineChart, e.g. something along these lines:

chart.value = bb.generate({
      bindto: '#chartDiv',
      data: {
        xs,
        columns,
        colors,
        type: line(),
      },
      point: {
        show: false,
      },
      line: {
        classes: ['chart-line'],
      },
      transition: {
        duration: 500,
      },
      axis: {
        x: {
          tick: {
            show: false,
            text: {
              show: false,
            },
            class: 'chart-line',
          },
        },
      },
      grid: {
        y: {
          show: true,
        },
      },
      legend: {
        show: false,
      },
      render: {
        observe: true,
      },
    })
  }

Which renders as this:

If I try to update the values with new values that contain fewer elements than before (e.g. a single XY line), then I end up with orphaned lines on the charts:

{
    chart.value.load({
      xs,
      columns,
      colors,
    })
  }
}

It is as if it hasn't flushed-out all of the previous lines from the old state, or am I doing something wrong?

[songololo]

For now I'm using unload() to clean out previously loaded lines:

chart.unload({
      done: () => {
        chart.load({
          xs,
          columns,
          colors,
          type: line(),
        })
      },
    })