When you place a water or lava bucket in another lava or water source or flowing block, it emits particles as if you we're breaking a block textured like lava or water.

Put the summary of the bug you're having here

*What I expected to happen was...: nothing
Describe what you thought should happen here

*What actually happened was...: block breaking particles were emitted
Describe what happened here

Steps to Reproduce:
1. Place or find any lava or water.
2. Place water or lava in the water or lava via bucket
3. Watch as block breaking particles are emitted.