In this puzzle
http://en.lichess.org/training/2622
there's a bug where after Qc7+, white plays f4 with the pawn, and then it allows you to take that white pawn with your pawn on e4. In fact, this is presented as the correct solution.
In this puzzle
http://en.lichess.org/training/2622
there's a bug where after Qc7+, white plays f4 with the pawn, and then it allows you to take that white pawn with your pawn on e4. In fact, this is presented as the correct solution.