Parentheses in command for state change

Why are parentheses not used after update here?

'Fulfilled': stategroup (
	'No' { }
	'Processing' {
		'Report Fulfillment': command {
			'Result': stategroup (
				'Success' { }
				'Failure' {	}
			)
		} => switch @ .'Result' (
				|'Success' => update ^ .'Fulfilled' = ensure 'Yes' ( ) 		//<--!!!
				|'Failure' => update ^ .'Fulfilled' = ensure 'Processing' ( )	//<--!!!
				)
			)
	}
	'Yes' {
		'At': number 'date-time' = creation-time
	}
)

While they are required after update here?

'Fulfill': command {
} => update (						//<--!!!
	'Fulfilled' = ensure 'Processing' ( ) 
)								//<--!!!

In the first code sample, you express that you want to update a single specific property, whereas in the second code sample, the braces express that you want to update a node (or more specifically: multiple properties of a node).

In terms of the grammar, you’re choosing a different target for the operation 'update properties'. See model/application grammar - Alan Application Platform for details.