This is quite possibly on purpose, but I don't know. :)

Minecraft Username: WhiteRaptor

Brief Description: Bonemeal can no longer be used on grass that is under a certain level of luminescence.

Instructions:
1. Make a dark room with a grass floor.
2. Right click bonemeal on grass.

How many times did you recreate this bug?: I used up a whole inventory of bonemeal before I noticed.

Result: No tall grass and flowers grew.

Expected Result: Tall grass and flowers.

Evidence: Really?

 

Nope, it worked before. And there is nothing about it in the 1.3.1 or 1.3.2 patch notes.
So either it is a bug, or it was done on purpose. I just want to know.