I have discovered this EXACT problem. Right at 20mph. It sounds like the car is literally groaning.
It typically happens on a cold start, slow to medium acceleration, and exactly at 20mph. I don't hit many stops in the morning on the way to work, so I only hear it once and the engines warmed up by the time I hit the next red light.
I did not. 74k miles later and it still does it lol. Every now and then I hear it when I'm paying attention but then I forget to look into it.Mine Acura RDX does the exact same thing at 20 mph and then it’s gone. Ever figure out what was causing the noise?