Popover arrow not working properly in the latest versions

[renatho]

Description

Popover arrow is working well on WP 6.0, but when I activate the Gutenberg plugin (from the repository), it's not working properly anymore.

Step-by-step reproduction instructions

The way to reproduce is through code.

1. In the editor, add a popover with the prop noArrow={true}.
2. Open it in an env with WP 6.0 and see it working properly.
3. Open it in an env with WP 6.0, and Gutenberg plugin (trunk) activated, and see that it doesn't work properly anymore.

Screenshots, screen recording, code snippet

Using WP 6.0 with Gutenberg plugin deactivated (working):

With Gutenberg (trunk) plugin activated (not working):

A case with Gutenberg plugin activated, with the Popover opening in the bottom (the arrow appears, but in a weird way):

A code snippet to test:

<Popover noArrow={ false }>
  <div style={ { width: '400px', height: '400px' } }>
    Lorem ipsum
  </div>
</Popover>

Environment info

• WordPress 6.0 with Gutenberg plugin activated (trunk) in Chrome.

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[mirka]

Confirmed as a regression introduced in #40740.

This is reproducing in Storybook, as well as the only place in the Gutenberg codebase where noArrow: false is used, which is the Add New Template popover in the Site Editor (go to /wp-admin/site-editor.php?postType=wp_template and click the Add New button in the top right)

Add New Template popover

Before

After

[ciampo]

Tentative fix opened #42874