`Insert HTML` unable to be saved, stripped out

[xmakina]

Setup schema.json

{
"attributes": {
    "body": {
      "type": "customField",
      "options": {
        "output": "Markdown",
        "preset": "rich"
      },
      "customField": "plugin::ckeditor.CKEditor",
      "required": true
    }
}
}

package.json

"@ckeditor/strapi-plugin-ckeditor": "^0.0.9",

Reproduction Starting with existing article

Click Insert HTML and enter some HTML

Expected The save button in the top right should be enabled

Actual The save button is not enabled. Adding some arbitrary text outside the HTML Snippet box enables the save button, but after saving reloading the page in the HTML Snippet is no longer present and has not been saved.

[xmakina]

FIX:

After entering HTML, the editor needs to click the green Tick Box to save the changes.