Duplication of block’s container element in Gutenberg 10.2.0

## Description
Right after upgrading to Gutenberg 10.2.0, some of my custom blocks (working with the API v2 and the useBlockProps() function) have now a double block container in the editor, like the following:

html
<div id="block-d0344daf-eb2e-467f-8905-5084c3783ff7" tabindex="0" role="group" aria-label="Block: Weather"
	data-block="d0344daf-eb2e-467f-8905-5084c3783ff7" data-type="custom-blocks/weather" data-title="Weather"
	class="wp-block block-editor-block-list__block">

	<div class="wp-block custom-block-weather block-editor-block-list__block"
		id="block-d0344daf-eb2e-467f-8905-5084c3783ff7" tabindex="0" role="group" aria-label="Block: Weather"
		data-block="d0344daf-eb2e-467f-8905-5084c3783ff7" data-type="custom-blocks/weather" data-title="Weather">

I’ve tested it on Gutenberg 10.2.0 RC1 and in WP 5.7.0 (Gutenberg deactivated), and this behaviour is also present there.

This issue was not present on Gutenberg 10.1.0/10.1.1.

The front-end side of the matter is working as expected, with only one container element and without any kind of issues.

## Expected behaviour
Blocks being rendered within only one container element.

## Actual behaviour
Blocks being rendered within two container elements.

## WordPress information
– WordPress version: 5.7.0
– Gutenberg version: 10.2.0
– Are all plugins except Gutenberg deactivated? Yes
– Are you using a default theme? Yes

## Device information
– Device: Desktop
– Operating system: Windows 10
– Browser: Firefox Developer 87.0b9, Chrome 89.0.4389.82