2019 Active noise cancelling= loud low rpm noise?

[waldo]

Hard to explain, but when I'm climbing up the mountain to my cabin the truck will get loud if the rpm drops in 3rd gear trying to hold a steady speed on a flatter spot. Goes away if I force a downshift.

Almost like a jake brake noise only going uphill.

You'd almost think the MDS came on going uphill is another way to explain it. But I suspect the microphones are picking up a harmonic and amplifying it.
Just seems too loud to be anything else.

Can't remember if it does it with the drivers window both open and closed.

Google search says there maybe a TSB/flash for the ANC but I don't know if it's for the same issue.