Version

5.2.0

Steps to reproduce

brower: firefox
renderer: svg

1.const mychart = echarts.init(dom, null, {
renderer: 'svg'
})
2. myChart.setOption(option)
3. option is pie chart or boxplot chart, and tooltip is configed to be show an trigger by item
4. hover in charti tem and move, the tooltip will be disapper

中文说明：当使用svg渲染时，在Firfox浏览器打开渲染pie或者boxplot，tooltip在hover时可能会不出现

What is expected?

hover in chart item and move, the tooltip will be show

What is actually happening?

hover in chart item and move, the tooltip will be disapper