My engine is just suggesting king shuffling too - very strange. I think I've found the win though, let me know if I'm missing something:
I've seen the engine just suggest random king shuffling before in these types of winning endgames. I don't understand why because it just wastes time. Maybe it's because the engine isn't calculating until mate, so it doesn't realize that these moves simply waste time? Not sure, but in this case I think the engine is right in thinking it is winning.
See:
https://www.chess.com/puzzles/problem/2752330
I'm convinced the ending position is a draw, and it's also a draw if you play Kb8 (like I did). For some reason if you play Kb6 the engine thinks you have a winning advantage. Of course black plays Rb4+ and you have to move the king, but you can't leave the pawn because then after Rxb7 it's a draw. So the engine just has you shuffling your king around forever while getting checked, meaning it's a draw.
So what is it about this position that confuses the engine?
Hopefully the mods will see this and delete the puzzle, but maybe not before posting a copy here for discussion.
You can't report puzzles anymore! (Not that it did much good and I bet most reports were bogus.)