You'll have to be fairly stern with them. Tell the service manager to take the car home and drive it like it's their own. That's what I had to do, even after showing up the second time with it in full slam-into-gear mode and my husband taking the service manager for a drive where he experienced it for himself. Contact the General Manager of your dealership and speak with them to reinforce that this is a known problem, and don't settle for them "resetting" your transmission ECU or simply replacing the shift solenoid. Also, ask for a loaner vehicle. It's likely they'll have your car for awhile. It's been 32 days for me now. Good luck!I took to the dealer. It's the same thing, they ran 15 miles but couldn't recreate the case. They told me they check the Hyundai "Black Box" records, there was nothing about transmission issue.
What I plan to do next is to print out all the postings about this issue in this forum, show them to the dealer service guy. All I want is I can bring the car in if this happens again and they will drive with me to experience the issue. If they disagree with it, I have write to their CEO or some high level manager.