All object fields are marked as required

I’m trying to create a dynamic field mapping for my automations/workflows using object fields.
While I’m able to list the fields correctly, all of them are flagged as required, which doesn’t match my expectations.

In the payload, the fields are marked as nullable (as described in the documentation):

body = {
	name: {
		title: 'User name',
		type: 'primitive',
		primitiveType: 'string',
		isNullable: true,
		isArray: true,
	},
	email: {
		title: 'Email',
		type: 'primitive',
		primitiveType: 'string',
		isNullable: true,
		isArray: false,
	},
};

Is the documenation outdated, the code wrong or is there a bug?