Nearly all of their practice programs are flawed. They present you with puzzles in which you find the "best move", but the moves the computer says are the best work off of a deeply flawed algorithm. It promotes getting check above all else, even when it is suicidal. Another example from my experiences with these puzzles is it presented me with a game in which I had the option to move my knight into a position in which it would either take the opponent's rook or queen, obviously the best move, however, their bot said that the best move was a suicidal check performed by my queen in which it could be taken out by a pawn. Yes, really. It constantly promotes these puzzles and analyses done by the bot, which needs improvement. This is why I do not recommend lichess beyond playing with people or friends. The community is great, the experience you can gain is great, but the bot they continually shove in your face will only serve to annoy you with its complete lack of ability to analyze.