echart地图散点设置，symbolSize: 1,时会出现散点逐渐消失，symbolSize: 0.5就正常了

Question

代码：

 series: [
        {
            type: 'scatter',
            postEffect: {
                enable: true
            },
            progressive: 0,
            coordinateSystem: 'geo',
            blendMode: 'lighter',
            large: true,
            silent: true,
            dimensions: ['lng', 'lat'],
            data: new Float32Array(),
            symbolSize: 1,
            /*symbolSize: function (val,params) {
                return val[2] * 1;
            },*/
            label: {
                normal: {
                    show: false
                },
                emphasis: {
                    show: false
                }
            },
            large: true,
            useWorker: true,
            steps: 2,
            itemStyle: {
                normal: {
                    shadowBlur: 10,
                    color: '#bad8ef',
                    shadowColor: '#258CF9'
                },
                emphasis: {
                    borderColor: '#fff',
                    borderWidth: 1
                }
            }
        }
    ]

一开始这样：

后面就剩下几个点了：