Ok so I was playing on line with my friend I was mining and I saw this glitch. So one block was light level 1 I think thats minimum light level then a few blocks a round it were light level 8 or something i dont know. The Nether Update has made it even more common. 

Steps to reproduce:

1. Place a torch. 
2. Type the command: /time midnight (i dont know if the syntax is correct. if it isnt then just wait until it's night.) 
3. The light will probably stop at a line of blocks