My Mom's 2017 Pat started bucking strangely on the 2nd-3rd gear shift(Hyundai/KIA 6-A Trans). Since it is under warranty for the powertrain warranty (only 48K Miles), I was going to take it in to the Dealer. But first, knowing the H/K 6-A is a really strong Transmission(unlike the CVT), I did some research on the Internet. There are lots of people with the same problem and it is not the Trans, it is prematurely failing Spark Plugs. I changed the Plugs, and sure enough that seems to be it. This happens on many 2.4 Engines(Patriot, Compass, Avenger, 200, et al). It sure felt like the Transmission(like it was low on Fluid), but this seems to have solved it. Much faster too. Google it.