Water is not updating anymore and you have to put a block under it to fix it again

The water is not updating, and there is a current now after the block is deleted in the water

What I expected to happen was...:
The water to be updated and for there to be no current

What actually happened was...:
It had a one block current going inward

Steps to Reproduce:
1. In a 2 height pool, put 2 blocks on top of each other
2. Delete the bottom block
3. Then delete the top