Is this tactics puzzle flawed? While solving puzzles on ChessTempo, I came across this puzzle:

[FEN "8/8/1p6/p1p3p1/P1P1B1K1/1P2kP2/5n2/8 w - - 9 1"]

1. Kf5


I played the intended correct answer,

[FEN "8/8/1p6/p1p3p1/P1P1B1K1/1P2kP2/5n2/8 w - - 9 1"]

1. Kf5 g4 2. fxg4 Nxe4


My question now, is this final position drawn, thus invalidating the puzzle?

I tried some lines but they all seemed to draw. Example:

[FEN "8/8/1p6/p1p3p1/P1P1B1K1/1P2kP2/5n2/8 w - - 9 1"]

1. Kf5 g4 2. fxg4 Nxe4 3. Ke5 Kd3 4. Kd5 Nf6+
5. Kc6 Kc2 6. Kxb6 Kxb3 7. g5 Ne4 8. Kxa5 Kxc4 {Tablebase draw} 1/2-1/2
Yes this seems to be a drawn endgame, most variations actually end up in a queen vs queen+knight situation which is generally a drawn endgame (one example below). But that doesn't mean the puzzle is flawed because as far as I know chesstempo puzzles are just about finding the best moves a priori, thus not always about a winning line. Good tactics trainers (such as chesstempo, lichess...) usually only say which side is to move, and the objective of the puzzle is actually part of the puzzle itself (that is, whether one is to play to mate, play to win material, or play to draw etc.) 

In this particular position black has to come up with the best moves in order to hold the game it seems.

 [title "One possible continuation, 1/2-1/2"]
 [fen "8/8/1p6/p1p3p1/P1P1B1K1/1P2kP2/5n2/8 w - - 0 1"]

 1. Kf5 g4 2. fxg4 Nxe4 3. Ke5 Kd3 4. Kd5 Ng5 5. Kc6 Kc3 6. Kxb6 Kb4 7. Kc6 Nf7 8. Kb6 Ng5 9. Kc6 Kxb3 10. Kxc5 Kxa4 11. Kd6 Kb4 12. c5 Ne4+ 13. Ke5 Nxc5 14. g5 a4 15. g6 a3 16. g7 a2 17. g8=Q a1=Q+ 18. Kf5 Qf1+ 19. Kg6 Qg2+ 20. Kh7