Bucket of sulfur cube replaces water(affects other replaceable blocks)

I use water for example, but it can be reproduced by placing down grass,fern,etc.

Actual behaviour:

When putting down bucket of sulfur cube on water, it replaces water source.

Expected behaviour:

The water source should be kept

steps to reproduce:

1. place a single water source

2. use bucket of sulfur cube on the block under the water source

3. observe the water source