LinkedIn API UGC Post Mention: share commentary is invalid

I'm using LinkedIn API to create posts. I also use the LinkedIn Mentions to create posts with mentions.

I can successfully create a post with mention except if I add in the message emojis or accents. Without mentions feature, I'm able to create any post with success.

Posts that work:

• Hello Stackoverflow
• Hello 😄 Stackoverflow
• Hellóó Stackoverflow
• Hello Stackoverflow (with mention to the linkedin page)

Posts that do not work:

• Hello 🤣 Stackoverflow (with mention to the linkedin page)
• Hellóó Stackoverflow (with mention to the linkedin page)

I receive the following error:

com.linkedin.content.common.ResponseException: share commentary is invalid

I send the following data to LinkedIn:

array (
  'author' => 'urn:li:organization:X',
  'lifecycleState' => 'PUBLISHED',
  'visibility' => 
  array (
    'com.linkedin.ugc.MemberNetworkVisibility' => 'PUBLIC',
  ),
  'specificContent' => 
  array (
    'com.linkedin.ugc.ShareContent' => 
    array (
      'shareCommentary' => 
      array (
        'text' => 'Hellóó Stackoverflow',
        'attributes' => 
        array (
          0 => 
          array (
            'length' => 13,
            'start' => 8,
            'value' => 
            array (
              'com.linkedin.common.CompanyAttributedEntity' => 
              array (
                'company' => 'urn:li:organization:X',
              ),
            ),
          ),
        ),
      ),
      'shareMediaCategory' => 'NONE',
    ),
  ),
)  

source https://stackoverflow.com/questions/69381494/linkedin-api-ugc-post-mention-share-commentary-is-invalid