What is the correct call on the following case: A set that was going the cross the net anyway, the blocker reached beyond the net, the attacker missed the ball, and the ball touched the blocker on the attacker side before the third hit.
In this case, I believe that the "block" is a legal hit. There are two particular rules I'll reference that I found in another answer. Basically, it is legal to touch the ball on the other side of the net so long as the ball is not moving parallel to the net, you do not interfere with the opponent's shot, and the opponent has made an attacking hit.
11.1 REACHING BEYOND THE NET
(11.1.1) In blocking, a player may touch the ball beyond the net, provided that he/she does not interfere with the opponent’s play before or during the latter's attack hit.
14.3 BLOCKING WITHIN THE OPPONENT’S SPACE
In blocking, the player may place his/her hands and arms beyond the net, provided that this action does not interfere with the opponent’s play. Thus, it is not permitted to touch the ball beyond the net until an opponent has executed an attack hit.
In fact, the previous answer provides an example from the official rules indicating a similar scenario and the correct ruling.
On a second hit, a player passed the ball near the net towards the opponent’s court. The ball did not penetrate the vertical plane of the net. In the 1st referee's opinion, no player of ‘A’ could possibly reach the ball. The blocker of ‘B’ reached across the plane of the net and blocked the ball. What is the correct decision of the 1st referee?
Even though it was only the second team hit, if the ball is moving in the direction to the opponent's court, it is an attack hit. Because, in the referee's opinion, no player of ‘A’ could possibly have reached the ball, the block of ‘B’ was legal. (Rules 13.1.1, 14.3)
However, this is somewhat difficult to call. If the blocking player interfered prior to the attempt by the attacker, it would be a fault. However, if the attacker missed his attempt prior to the blocker's touch, I believe it to be a legal hit.