the top of the block not having a collision is not an error, visually as the block is 3D you would be kind of behind the block and the top of it is blocking the view of someone who is looking from above. The collision is on the block the ghost is on, but I already have a solution for that, I would just put a smaller hitbox for the player to give him time to change positions, it will make the game much easier, but at least the Tetris will not kill you as soon as you are on the same block as him.
Wow... thank you for the feedback!!