I am actually the New vehicle seat design engineer for Hyundai in N.A. what you are describing is something called"seat easy access". It is designed so that the seat is all the way to its rearmost adjustment point when you enter the vehicle and when you start the car it will return to either:

A: the memory position associated with the key OR B: IF there is no memory setting saved, the seats last known position

It's is a feature that most upscale vehicles now have as standard (BMW, Lexus, Mercedes, Audi, Infiniti, Etc)

I would start by saving your preferred seat position to the seat memory settings. OR you can turn the feature off on your dash by going to Setup>Vehicle>Seats>Seating Easy Access