Hello,
I just noticed that when you go to 'Categories' and then try to edit one, there is no language switcher and if you put lang tags ([:en]...) in fields, they appear in the 'edit post' pages (in the 'categories' box).
Also when you look at the posts list, lang tags ([:en][:fr][:]...) appear instead of the translated string in the column 'Categories'.
Tested with WordPress 4.5 and Qtranslate X 3.4.6.4, no other plugins activated, and with Twenty Sixteen 1.2 theme.
Best,