I didn't see the play, but there are a few reasons why a block might not show up:
1. When a player is driving to the basket and has her shot "blocked" before her hand is in shooting position, it is supposed to be called a steal instead of a block.
2. I can testify from first-hand experience that it is sometimes tough to see a block, if it's more of a tip than a complete rejection, when seated at the scorer's table.
3. When there is a flurry of missed shots and rebounds, with a block in the middle, sometimes the scorer forgets to key in the block since the missed shots and rebounds have a higher priority, i.e. they must balance in the box score.
As for rebounds, ultimately each shot HAS to have a rebound - and it is impossible for the scorer not to ultimately give a rebound to someone. I can think of two situations where you and the scorer might disagree as to whether a rebound happened. The first would be if a player briefly grabs a rebound and then loses it or has it stolen. In that case it is a judgement call as to whether it is a rebound followed by a turnover or simply a rebound to the opposing team who ended up with the ball. Secondly, it is also a judgement call when a player attempts to tip in a rebound at the offensive end. It can either be a rebound and a missed shot - or it can be nothing. There is also one situation where a rebound can be attributed to one of two players. That is when a player tips a rebound to a teammate. If it is a controlled tip, then the first player should get the rebound. If it is just batted while trying to control the ball, then the second player would get credit. This can also happen (rarely) on a blocked shot, where the player who blocked the shot also gets credit for the rebound.
