Cactus do not damage players or other entities beyond a specific coordinate.
above x- 1,048,575 no damage from north and south face of cactus
above z- 1,048,575 no damage from east and west face of cactus
negative cords are also effected at same number.
Replicated on multi player and single player.
Environment
win 7, centOS 7 Java 7
Confirmed. This issue has an interesting cause: the hitbox of a cactus is smaller than the hitbox of a normal block. However, above the specified coords, the hitbox suddenly becomes a full block. This makes it impossible for the player to touch it. A better title would be: "Cacti have a wrong hitbox over x/z +/- 1,048,575".