The en passant mate was not legal because its officially mate in 7
and you dont know what happened before
Black 2 Play Mate in 1
Also Keep in mind you are viewing it from the white players perspective
Nxc4#
ye I just thought people might not see that Rxg8 is not mate cause the pawn takes back
Knite to c4.
The solution of the first puzzle I have found without hints: knite to c4
White to play mate in 1
Black to play mate in 1
White- d4=N
Black- Nb7
The en passant mate was not legal because its officially mate in 7