I know that there are some mistakes in the CT-ART 3.0 software. I just happened to come accross one today.
I arrived at this position and instinctively chose Re4#. I got it wrong! I thought to myself, "I must've had a slip of the mouse." So I moved Re4 again ... WRONG! Now I was mad. The "correct" response is g5#. So I played the current position and sure enough, Re4 is checkmate.
Just an FYI.