Water on soul sand or magma blocks does not disappear when dispenser or sponge picks it up

When using a dispenser to pick up water if the water is on soul sand or a magma block the bucket will be filled but the water will stay causing the water to be duplicated.

Steps to Reproduce:

1. Place soul sand or magma block
2. Place water on top of the soul sand or magma block
3. Place a dispenser next to the water
4. Place an empty bucket inside the dispenser
5. Activate the dispenser

Observed Results:
The water does not disappear, but if you open the dispenser, the empty bucket will be filled.

Expected Results:
The water should disappear.