No @KazuyaKan, chapter 19 only had 3 parts and this is an extra, hence the .5 which is often used for extras. Though I get it can be confusing with parts...
I see. Even if not for this particular story though, I still dislike the practice especially when it's obvious in certain manga that the chapters are chopped by the scanlators.
Just had to find some dumb excuse to get the glasses out, eh? She stopped wearing it because her bad eyesight healed, so it became blurry, and now she wears it to 'help' with her eyes when reading, whot the f?