That is actually a fantastic study with an amazing key move. On top of it, the key move is echoed two moves later by a similar "double take" sacrifice of the g-pawn. It is impossible that such a study would only score a 4th commendation. It's one that deserves to be in everyone's miniature top 10!
Endgame Study - J. Nunn, 2014, 4th commendation.
Yes, that thought occurred to me too. "Partially anticipated" or "after .." like my version of Alievs study. Nunn is a pretty competitive character though. As a GM and a multiple world champion problem solving. I was honored to finish as 3rd during a strong study solving tournament in Wijk aan Zee in 2013. Behind his 1st place of course!
White to play and draw.
https://www.chess.com/blog/lodrac91/j-nunn-2014-4th-commendation