If you right-click with water/lava bucket on pre-existed water/lava, it creates particles that normally appear when block broke. Happens both in survival and creative.
Environment
AMD FX6100 3.3GHz
4GB RAM
NVIDIA GeForce 7025
233GB Hard disk
Windows Vista Home Premium K SP2 32bit
java version "1.7.0_21"
Java(TM) SE Runtime Environment (build 1.7.0_21-b11)
Java HotSpot(TM) Client VM (build 23.21-b01, mixed mode, sharing)
29th Duplicate of MC-18365, please use the search function to see if your bug has already been submitted. Currently over 57% of tickets are being closed as duplicate.