[5.x]: When the Content Block field contains a Matrix field, creating a draft results in an error: Attempting to duplicate an element in an unsupported site

What happened?

Description

When the Content Block field contains a Matrix field, creating a draft results in an error:
The draft could not be saved.
Attempting to duplicate an element in an unsupported site.

Steps to reproduce

The record screen: https://www.awesomescreenshot.com/video/48581983?key=a149ff40afc09785bf1a5af480e71c84

1. When the Content Block field contains a Matrix field in entry.
2. Click the Add a site...
3. Click the Create a draft

Expected behavior

Create a draft

Actual behavior

Get a Error.
Unsupported site – craft\errors\UnsupportedSiteException
Attempting to duplicate an element in an unsupported site.

https://github.com/user-attachments/assets/c776ae2f-9569-4196-bf21-590e50c54b2e

Craft CMS version

Craft Solo 5.8.23

PHP version

8.2.19

Operating system and version

Linux 6.6.87.2-microsoft-standard-WSL2

Database type and version

PostgreSQL 15.15

Image driver and version

Imagick 3.7.0 (ImageMagick 7.1.1-13)

Installed plugins and versions

No plugins are enabled.

Start with the record-screen reproduction using a Content Block field containing a Matrix field, then trace the UnsupportedSiteException reported when selecting a site and creating a draft. Done means the draft is created successfully without the unsupported-site error in the reported Craft CMS and PostgreSQL setup.