Here is the California court precedent:
"The power of decision vested in the trial court is to be exercised by a duly constituted judge, and that power may not be delegated to investigators or other subordinate officials or attaches of the court, or anyone else .... It is the constitutional right of every citizen and every litigant to be governed by the law as expounded by the judges, and not by officials or employees provided by the legislature to assist a judge in an administrative or quasi-judicial capacity. Such help as may be accorded a judge to assist him in the exercise of his judicial functions may never be permitted to reach the point where someone else decides the case or an issue before him."Yes, Judge Heather D. Morse does it anyway. Technically, the parties need to object, and make sure that the evaluator is just giving a recommendation that requires further court action.
In re Marriage of Matthews (1980) 101 Cal. App. 3d 811 [161 Cal.Rptr. 879]