Su oración no fue añadida porque la siguiente ya existe.
It was originally written with a question-mark in the Japanese.
For me it's odd ...
But I want other native opinions.
I don't think it's a typo. It probably depends heavily on context, and the question part of it is implied. e.g. "I don't intend to swim; should I bring swimming trunks anyway?".
I don't think it's an explicit question. (Although I do think the English translation should be "have no intention of")
Using Yahoo there are four examples of つもりはないんよ？ in the first forty hits. I copied them here so you can find them yourself if you want to ponder what differences in nuance there are when using ？.
イヅルにかて、渡すつもりはないんよ？
「イヅル...僕は、お前を捨てたつもりは、ないんよ?」
そんなつもりはないんよ?」 笑いながら、里は謝った。
いや、べつにあのボーカルを否定するつもりはないんよ?(迎合もできてないんやけど
