Phantom glitch on The Arbiter

To look at the "Phantom Glitch on The Arbiter", as soon as you start the level "The Arbiter", turn around and zoom in on the Phantoms. After watching them for awhile, they disappear into the clouds and spin out of control, one even crashes into a platform below. The other two will keep on falling until they hit the bottom of the level. This probably happens because Bungie only planned for them to travel a certain distance and upon reaching the end of their route the game physics take over.

Trivia

 * Sometimes, when spinning, a Elite will fly out, and disappear in barely a second.