Engine Sound Of The Db Br 422 Not Audible Everywhere

Hello, I noticed that when you drive a DB BR 422 in double traction, you can only hear the motor sound at the front and in the middle of the train (at the point where the trains are coupled). But you don't hear the engine sound at the end of the train. You can hear something, but it's just the rolling sound of the train. I noticed that when I first drove this train.

 

Hello,
Is the bug in a specific route or in PRO and HHR?

 

because I don't have the HRR at the moment, I only noticed the bug in RRO

 

I was playing a couple of services with the 422 in PRO and i noticed it too.