Black (squares?) on 3rd person view

Just see the images, black (squares?) (see the first image, 2012-11-17_01.28.59.png) on 3rd person view (both).

• It seems to happen on the coordinates shown, on SP and MP (try /tp player 124 58 651). (see screenshot 7) (reproduced)

• This square remains on the back.

• Sometimes (see screenshots 10, 11 and 12) dissapears when flying towards it, but it reappear on coordinates shown. (see screenshots 3-6)

• Does not happen on superflat worlds.

• Graphic Cards up-to-day (OSX).

• No mods used, default texture pack.