The bug is that when creative was creating the pyramid of Beacon covered it and saw Beacon textures disappeared. The bug is in the textures of the sides. Here are some pictures. Respond below if happens in other versions, if so you have to fix it.
MC-2616
Bug in Beacon textures.
Resolved
Duplicate
0
Nothing Personal Kid
(Unassigned)
Unconfirmed
block
Minecraft 1.4.2
Retrieved
Duplicate of: MC-1791 - Please use the search function to see if your bug has already been submitted. Currently 25% of tickets are being closed as duplicate.