I'm not sure what you mean by template, but however this is fixed, I see the most egregious problem being almost a security or privacy issue. I have never issued an invitation without a personal message included, and it is a bad thing that the message just sits around afterwards. Anyone who issues an invitation may be (in fact, probably is) clueless that the text remains there afterwards. And worse, the next mod to issue an invitation may be clueless that the previous personal message sent with an invitation goes out again by default unless they change it. This is just a bad situation.
And for the many foreign groups it is even worse. Even if you write an invitation in their language, the surrounding text is in English, so you have a language mix which is confusing.