Builder can't build water blocks

The builder can't seem to place water blocks when I run a schematic with water source blocks in it. It fails with "unable to do it". I have two water buckets in my hotbar. I made a [schematic](https://github.com/cabaletta/baritone/files/3365227/water.schematic.zip) with two water source blocks side by side to illustrate the issue. Ideally baritone would be smart enough to do water duplication and make unlimited water from two buckets. I haven't done Java in years, looking to brush up on my skills.
If you would like some help with this issue I might work on it and submit a PR. Been reading your code in my spare time, very interested in this project.