Quoted from JimFNB:
It should fit unless the folded back box is wider than a standard pin. I’ve hauled several pins in my 2015 Santa Fe sport.
You have to take off the back seat headrests, slide the folded back seats up as far as you can, and then push down hard on the back seats while you slide the pin in. Much easier if you have a helper.
I'll have to try again at some point. Tried twice now (both Sterns) with same result, yes, removing the head rests and sliding the seat forward (the second time anyway).