Map widget doesn't show map inside list widget

**Describe the bug**
Map widget doesn't load map inside a list widget whenever there is already a value entered.

**To Reproduce**
1. Create `list` widget containing a `map` widget
2. Define a point on a map and publish page
3. Load up published page, open widget

**Expected behavior**
Map widget loads map

**Screenshots**

**Applicable Versions:**

- Netlify CMS version: [e.g. 2.0.4]
- Git provider: GitHub
- OS: MacOS Mojave, MacOS Bigsur
- Browser versions: Chrome 83, FF 81
**CMS configuration**
```js
const Gallery = {
label :'Gallery',
name :'gallery',
folder :'data/gallery',
create :true,
slug :'{{slug}}',
description :'Collection of image galleries',
fields: [
{
label :'Title',
name :'title',
widget :'string',
},
{
label :'Gallery',
name :'gallery',
widget :'list',
label_singular :'item',
fields: [
{
label :'Coordinates',
name :'cordinates',
widget :'map'
},
{
label :'Image',
name :'image',
widget :'file',
allow_multiple :false,
},
{
label :'Caption',
name :'caption',
widget :'string',
required :false,
}
]
}
]
}
```

**Additional context**
The maps seems to render when the list widget is set to `collapsed: false`. However if list items moved around in closed state maps are failed to render.