What is this noise?

[John336]

S7 Facelift, what is this noise after the engine has been running idle (660rpm) for exactly 5 minutes on gear P or N?
https://youtu.be/GRFTorTzg8U

The noise can also be heard right away without waiting if the idle rpm is raised to over 800rpm (over 1200rpm and engine noise overwhelms it). The frequency of the noise does not change/follow engine RPM.
The noise goes away for exactly 5 minutes if you change the gear to any other position and then put it back to P or N.
There is no noise after a cold start until transmission fluid is approximately at least 30C (86F).

Possible sources that are near where the noise comes from (behind the front left wheel, the noise can't be heard from the right wheel side or engine bay) :
0B5315105R (08/2016 superseded by letters AB) Gearbox oil pump
079121601A Additional coolant pump (Engine Coolant Circulation Pump 2 V178 in the SSP 607)
079965561 Additional coolant pump
079121013R Coolant pump
8K0965567B Coolant pump (Charge Air Cooling Pump V188 in the SSP 607)

There are no error codes and the car works fine, no audible noise when driving.
The failed PCV was replaced on August 2022.