Sponges do not "suck up" water

Sponges no longer suck up water.

I was trying to quickly get rid of natural waterfalls
with sponges, so the water quickly disappeared...

But instead, the sponges only took up block space,
and didn't erase the surrounding water, nor turn into wet sponge blocks.

Steps to Reproduce
1. Find/make a waterfall
2. Place sponge on source block's location
3. Observe how the sponge didn't erase nearby water, nor turn into wet sponge