If that's the only time you have noticable vibrations, congrats ... you don't have the shake. Have the dealer triple flush the transmission fluid and change the filter. Fill with Mobil One or whatever new fluid they have for it. My '15 had the shake. My '18 doesn't. Any vibes I experience now are tire and surface related. I'll address the tires in about 10k more miles and get the same transmission service I suggested to you shortly before/after. My 2cents Sent from my SM-G950U1 using Tapatalk