Is a whine in the AC unit a common problem, but difficult to find and fix?

What is your question?

A high pitched whine or groan is always there when 2018 Escalade accelerates, usually between 10 mph and 40 mph. It is not noticeable at higher speeds or when vehicle is idling. The Dealer Service can not locate the cause or the solution. They claimed to have found a leaf in the cage and claimed to have replaced the fan, but did not provide any written documentation of such. Other Cadilac Dealer service centers deny ever having heard of such a problem. It is annoying enough to get on ones' nerves.

What makes this problem better or worse?

It's worse when accelerating from 10 mph to about 40 mph

How long has your 2018 Cadillac Escalade had this problem?

Since buying the car. 3 years in July