2017 Golf 7 DSG Vibration on Floor while Idle

I brought my car to my mechanic and he wasn’t able to figure it out so I wanted to have some possibilities before going another one.

The car in question is Golf 7, DSG 125 PS at 16k km. For a while now, whenever the car qoes to idle, after 1 sec there was feeling of vibration. After some trial and error, I noticed I don’t feel the vibration when I lift my feet from floor. There is no vibration in wheel or pedals or gear, only from the floor.

Any advise to point out to the mechanic next time I bring my car? Thanks in advance