Hmm could be, cause 1. gear at low speeds, maybe 2.
Then the more steering angle you have, the more difference between right/left diff output to the driveshafts! So of course diff is working more whether it's a LSD or open one, and cause of the high gear ratio on low gears the noise is much louder.
Have to listen on ours on low speed steering angle, but I only have the lower purple powerflex one. And for me yes I hear a slight whine if the N is just rolling on 4. 5. 6. with no load but gears engaged.
Because used to much louder working noises on other cars, the N is like a Maybach or RollsRoyce to me.