I was testing in a self-made NAS (Debian + OpenMediaVault) and I was not getting SOME translations.
Some translations worked OK but some others were ignored.
The problem was caused because I had not added that locales to my NAS locale:
1) Edit file /etc/locale.gen
2) Check if your locale is active (written and uncommented).
3) Execute "locale-gen" as root (or sudo).
So, in short, if you have a Linux system and your translations are ignore check if you have that locale active in your system.