Right click a block which already has water or lava on it using your bucket of water or lava and it displays the block breaking effect.

I expected the bucket of water or lava to just add substance onto the block as it would in previous versions.

Then when I poured the bucket onto the block with the substance on it already, it displayed the block breaking effect (particles fly, noise of block breaking, etc.)

Steps to Reproduce:
1. Go on a creative world.
2. Pour a bucket of water or lava onto a block which already has the substance on it.
3. Watch the unusual effect.