CKEditor5 not saving from CiviMail but save correctly from Civi Event and Civi Contribution

Using CKEditor5 for civimail. Content and images are not saved when saving draft or any save of message.

Using D9 with Civi 5.44. CKeditor4 saves correctly as well as text editor.

Also, CKEditor5 saves content for Contributions and Memberships. No obvious errors in Drupal Error log or other OS logfiles.