SiriusB You're right, it's a bug of this menu type in template in J4.
You can open the same XML file: /templates/ja_alpha/html/com_content/article/services.xml
change this line:
<fieldset name="request"
addfieldpath="/administrator/components/com_content/models/fields">
to:
<fieldset name="request"
addfieldpath="/administrator/components/com_content/models/fields"
addfieldprefix="Joomla\Component\Content\Administrator\Field" >