2019 GLC350e Sport 4matic transmission problem

I have recently purchased a used 2019 GLC350e and have found an issue first thought to be brake related. When in charge mode which keeps the engine running at all times even while braking, I would feel a sharp almost violent vibration through the brake pedal when almost to a complete stop, it was alarming and difficult to leave my foot on the brake pedal till completely stopped. This was not felt in hybrid/ electric mode where the engine was not running and or would shut off during braking. I brought it back to the dealership where purchased and thankfully had a short term warranty. Two transmissions, yes two, new engine and transmission mounts and almost 4 months in and out of the service department later, the vibration is now felt from what seems like coming from the transmission itself and as an added bonus I now have a high pitched whining noise that can be heard even with the radio on, this noise graciously appeared after the first replaced transmission. I was told by the service writer, manager and their expert on hybrid and electrical vehicles that this noise is from the generator within the transmission and is within Mercedes tolerances, also that I should feel lucky as I now have a two year warranty on my transmission and the replaced mounts. My question to this awesome forum, has anyone else experienced this noise and vibration and what was done to fix it?
Thank you all