该问题是怎么引起的？

这种数据会引发报错
"categories": ["2016", "2017", "2018", "2019", "2020", "2021"],
"series": [{
"name": "成交量A",
"data": [null, null, null, null, null, null]
}, {
"name": "成交量B",
"data": [70, 40, 65, 100, 44, 68]
}]

重现步骤

可以使用在线演示页面，然后输入上面的数据，鼠标移入图形，弹窗出不来，在小程序中点击报错

报错信息

VM270 WAService.js:2 TypeError: Cannot read property 'x' of null
at getToolTipData (vendor.js?t=wechat&s=1629286054600&v=bee3698026883029e8b056804400e2b3:10863)
at uCharts.define.push.92.uCharts.showToolTip (vendor.js?t=wechat&s=1629286054600&v=bee3698026883029e8b056804400e2b3:16789)
at VueComponent._showTooltip (qiun-data-charts.js? [sm]:1191)
at VueComponent._tap (qiun-data-charts.js? [sm]:1254)
at vendor.js?t=wechat&s=1629286054600&v=bee3698026883029e8b056804400e2b3:1299
at Array.forEach ()
at vendor.js?t=wechat&s=1629286054600&v=bee3698026883029e8b056804400e2b3:1256
at Array.forEach ()
at Ui.handleEvent [as __e] (vendor.js?t=wechat&s=1629286054600&v=bee3698026883029e8b056804400e2b3:1246)
at Object.i.safeCallback (VM270 WAService.js:2)