In this puzzle, it is also possible to mate with the rook in the end. This puzzle should be removed as both mates seem correct.
lichess.org/training/F9dBRHope it is fixed soon.
Regards,
Hai_Schrei
Nifty puzzle.
Particularly since it is the last move in a mate, why isn't having this trivial (in this case) choice fine? Certainly seen similar in other puzzles before. Yeah, typically you expect puzzles to have only one correct choice for each move but the "either queen or rook is fine enough for a last move promotion mate" is a special case that pleads for an exception to the rule. Plenty of times where a rook is sufficient for a last move promotion and would be a shame to dump a fine puzzle just over this. And really, who would get that far in this puzzle and then falter over this? It's a common issue one should be able to easily shrug off, even if it may cost you a few extra microseconds of brain processing.
Maldito puzle
Two different backrank promotion M1 is fine (both show up correct too).
In lichess puzzles, there is always only one correct move, UNLESS it's mate in one; then, there can be multie solutions. Rest assured that all puzzles are computer-generated, so a mate in one wi never be overlooked (i.e. if your move is mate, it will be counted as correct).
Thanks for your answers! I now got it.