Steps to reproduce

1. Setup editorial workflow, using the example from https://doc.ibexa.co/en/latest/guide/workflow/#workflow-configuration.
2. Setup RichText custom tag with the required parameter.
3. Log in as a content editor, and create a new content item. Add a custom tag with missing required parameters and send content to the legal stage.
4. Login as a legal team user and send content to the done stage.
5. You should get the following error:
   Argument 1 passed to Symfony\Component\Form\Form::get() must be of the type string, int given, called in /app/vendor/ezsystems/ezplatform-content-forms/src/lib/Content/View/Builder/ContentEditViewBuilder.php on line 102 [in vendor/symfony/form/Form.php:941]

We are investigating the issue, and we are preparing PRs.