Hi Smokie,

It's called "inviting" because you use the invite feature to add someone, but the PM received is worded exactly the same as when you used to add members manually to your board.

This is what a member used to get when they were manually added to a board
You were given a membership on board name. The Administrator that changed the level was admin name, you can contact them by sending a private message

And this is the message people receive when you use the invite feature.
You were given a membership on board name.
The Administrator that changed the level was: admin name, you can contact me by sending a private message.
Well I'm not sure whether those messages are supposed to be the same or not, but currently they are:)