A: The way chess engines work (an extremely simplified explanation) is by attempting every possible continuation to the given position on the board and then analyzing the resulting position. Because the number of possible responses to every possible move grows exponentially with each subsequent move, and the chess engine has a limited time to analyze each position in the game, it can only analyze up to a limited depth (i.e. how many moves ahead). It is quite possible that just past the last analyzed move in the suggested continuation there is something that leads to a loss of material, or even a checkmate. The chess engine simply hasn't looked that far ahead. It if has, it would have chosen a different move prior to that, or 2 moves prior to that, etc..
In light of that, the last few moves in the suggested continuation shouldn't be "trusted" as much as the earlier moves. The playing strength of a chess engine is generally proportional to how deep they can analyze the position (i.e. how many moves ahead). Grandmaster level is 10-15 moves deep. However, near the end of the suggested continuation the analysis depth is only 1-2 moves, which makes it a beginner level. But it doesn't invalidate the entire suggested continuation in any way. It's just the way chess engines work in general.
