Yes, the 2.4l, 2.0t also known as the Theta II is the majority of their problems. They claimed it was fixed with the re-design that detuned it to 185hp in 2015, but then those started failing too. The 2.0nu (non-turbo) seems to be less problematic, though its earlier 1.8l version did end up having less severe problems related to piston slap and scored cylinder walls.
I had a Theta II 2.4l in my Sonata that I got rid of when it first started showing signs of trouble. It ran nice for the most part, and had plenty of power too. An otherwise very nice car.
As another post wrote above, they seem to be giving less hassle about replacing them. I just didn't want to go through the trouble/hassle of dealing with the breakdown.