Building a repeated schematic, it often skips the last block

## Some information
Operating system: Linux 18.04.5
Java version: 8 (282)
Minecraft version: 1.12.2
Baritone version: 1.2.15
Other mods (if used): Kami Blue, Forge Mod Loader

## Exception, error or logs
There is no error in the log, simple odd behaviour in the game.

## How to reproduce
Any idea why Baritone building a schematic often skips the last block. In my case it's the top right block in the image - errors indicated with the Magenta circles. My schematic is to built diagonal highways and the schematic is a 1x4x7 (width x height x depth). Basically 7 blocks of Netherrack on the bottom layer, and One block of Netherrack on each end on layer two. The rest is air. I use buildrepeat, but as you can see from the screenshot, often the top right block is left behind, when it should have been Air. I'm using Baritone 1.2.15 release version from Github, running on Minecraft 1.12.2 on the Constantiam server.

In the nether, digging a highway in NE direction.

```
buildrepeat 1,0,-1
build diagonal-dig-medium-23wide.schematic ~ 118 ~
```

Even if I disable the Kami Blue mod, it still does the same. So Kami Blue is not affecting the outcome.


Here is the schematic file.

[diagonal-dig-medium-23wide.schematic.zip](https://github.com/cabaletta/baritone/files/6562880/diagonal-dig-medium-23wide.schematic.zip)

## Modified settings

- rightClickSpeed: 2
- buildRepeat: 1,0,-1
- allowSprint: false
- blockReachDistance: 4.5
- useSwordToMine: false

## Final checklist
- [x] I know how to properly use check boxes
- [x] I have included the version of Minecraft I'm running, baritone's version and forge mods (if used).
- [x] I have included logs, exceptions and / or steps to reproduce the issue.
- [x] I have not used any OwO's or UwU's in this issue.