I'm not sure how did your dealer "flush" your SkyActiv automatic transmission? There's no ATF lines coming out to radiator for cooling, hence there's no way to hook up the ATF flushing machine. I suspect your dealer did the drop-pan ATF change at most, without changing ATF filter cartridge inside. And there's no gasket for transmission fluid pan, only sealer is applied around the pan.
hmm you by be right. All I know is next time I'm going to do it myself.