It seems some of the bugs are because font creators and sublime dont sync.
Most of the modern fonts have "Regular", "Italic", "Bold", "Bold Italic" typefaces at lease. So, Sublime does not catch the default "Regular" type, and if you set font_face to "Some Font Regular", you lose bold and italic, because Sublime cannot find it, as it appends "Bold" and "Italic" keywords to look for a font. Obviously "Regular Bold" does not exist.
For fonts whose regular type consists only of a name "Some Font", everything's fine.
So since you cannot make font designers to name fonts as we want, SublimeText should be made capable of defining font sets manually, like "font_face": ["Font Regular", "Font SemiBold", "Font Italic", "Font Compressed Bold Italic"].