It's been discussed before on this forum after the Watford game; when he failed to anticipate the ball over the top and was slow off his line and when he did come off it he didn't fully commit and was stranded in no man's land and was beaten at his near post.
Every keeper makes mistakes, and yes he has saved us (forgive the pun) more points than lost. But if he is to become a top class keeper and this part of the game has to improve. He first made this 'error' against Leicester earlier on in the season for Vardy's first (granted Basham was more responsible then).
It happened again today. Now in mitigation he perhaps didn't want to hurl himself at the ball as was aware he was the sub keeper, we were winning 2-0 and it is an FA Cup game which would pale in significance should he get injured and it was a fine finish.
Nevertheless it's the third time this season that he has been conceded this sort of goal that I've seen. Something that he needs continuous training on that I'm sure that he's getting.
He could do much worse than try to learn from the best in world football at this skill: