"File chmod mask" not applying to metadata files

I have “File chmod mask” set to 0664, however the metadata files created by nzbdrone are always 0644. I’ve tried deleting the metadata files and rescanning so a fresh set of files are created, and they are still 0644.
If you could make this setting apply to metadata files that would be great.

Version: 2.0.0.1861
Mono Version: 3.2.8 (Debian 3.2.8+dfsg-7)

Added to Trello: https://trello.com/c/HAgderxC/803-chmod-for-metadata