I have an '18 and have the sensation of a wobble or shimmy on low speed turns and acceleration, through about 20-25 MPH. I have my car serviced with the dealer and over time have come to trust the service manager for both his attention and honesty. I recently left the car for a day and he concurred (there is a service bulletin out on this as well and there are more posts in this forum with additional information) that there is an issue. They ordered the parts (short drive shafts in the front wheels I believe) and the car will receive this update once they receive the parts. Suggest you continue to push back with the dealer, research additional media here on the forum and on the internet so you have additional leverage when you bring it back again with the same issue. Mike at my dealership was not familiar with the issue until my email request to him, he researched it, then they kept the car for the day I brought it in for regular maintenance. Upon return of the loaner, he stated they would be changing the shafts that he had to order once the dealer receives them. So I do believe you probably are experiencing the same issue.