I realised, when editing a post a second time, I got an additional +2 rep. Does this make sense?
I think it's ok once. Is it possible to restrict it?
I don't think that is a problem, as you are improving the post.
If you are worried about gaming to increase reputation: after you reach a certain reputation, you are able to make edits without needing approval, and at that point, you stop getting the +2.
And, you do need approval before that.