Put the summary of the bug you're having here

I tried walking down a hill where a stream, flowing from one source block, was flowing. I had frost II diamond enchanted boots, and it basically turned the stream into a lake.

What I expected to happen was...:
Well, I honestly didn't know what to expect.

What actually happened was...:
As I kept stepping on the water and going down the hill, more source blocks were created.

Steps to Reproduce:
1. find (or make) a stream that flows down a hill
2. enchant diamond boots with Frost Walker II
3. Walk down the hill from the top of the stream to the bottom repeatedly
4. voila, a lake is formed!