Bukkit

What steps will reproduce the problem?
1. Enchant a bow with featherfalling to make the teleportation bow.
2. Shoot arrow at a wall or up through a ceiling.
3. Glitch through the wall/ceiling about 10% of the time.

What is the expected output? What do you see instead?
Should not be possible to glitch through blocks, but it is.

What version of the product are you using?
Latest.

Do you have an error log of what happened?
No errors.

Please provide any additional information below.
Currently it's possible to glitch through walls, up through floors/ceilings, and through doors using the teleport bow. It's similar to how you can glitch through blocks using ender pearls, but much harder. It is difficult to do it with this bow but still definitely possible and we've had people use the bows to glitch into private houses/towns to kill people inside, even if they were completely sealed off.