masktoolsのFixが来てる
https://github.com/pinterf/masktools/releases/tag/2.2.12

> Changelog
> v2.2.12 (20180107)
>
> Fix: mt_merge 10-16 bits: right side artifacts when clip is non-mod 8 (non-AVX2) or mod16 (AVX2) widths
>
> Earlier changes
> v2.2.11 (20180105)
>
> Fix: mt_merge luma=true: broken output when: 8-16 bits AVX2, 32 bit float: SSE2, AVX
> move project to VS2017, vs141_xp toolset