Note block doesn't play when hit with sword

Before 1.6.1, hitting a note block with a sword in Creative mode would just break it. However, what should happen now is that, instead of the sword breaking, the note block's note would be played. WHat actually happens is that the note block still doesn't break, but no note is played.

How to reproduce:
1. Open a world in Creative mode
2. Place a note block
3. Hit the note block with a sword