🐛 [BUG]漏斗图渲染异常

### 🐛 Bug description [Please make everyone to understand it]

> Please provide a link by forking these links [G2Plot](https://codesandbox.io/s/g2plot-issue-template-gzfdq?file=/index.ts) or GitHub repo, a minimal reproduction.

* _Required_ **Link to minimal reproduction**:

### 📷 Step to reproduce
https://codesandbox.io/s/epic-platform-9fgbm1?file=/index.ts

```
import { Funnel } from "@antv/g2plot";

const data = [
{
value: 5149,
field: "2020-08-05"
},
{
value: 16098,
field: "2020-07-03"
},
{
value: 5189,
field: "2020-05-26"
},
{
value: 4698,
field: "2020-05-15"
},
{
value: 840,
field: "2020-03-11"
},
{
value: 4297,
field: "2020-03-07"
}
];

const funnelPlot = new Funnel("container", {
data: data,
xField: "field",
yField: "value"
});

funnelPlot.render();

```

### 🏞 Expected result

### 🚑 Any additional [like screenshots]

* **G2Plot Version**:
* **Platform**:

Start with the linked CodeSandbox and run the reproduction in index.ts using the Funnel import from @antv/g2plot. Compare the rendered funnel with the attached screenshot and investigate the chart behavior responsible for the abnormal rendering. Done requires a confirmed rendering fix, but the issue does not state an expected result or provide version and platform details.

Written by the indexing model from the issue text.