If I make a post with % in it and then go back and edit the post the first % gets changed to %. If there are any other % in the post they remain unchanged. If I then edit the post again the next % in the post gets changed to % again not affecting any remaining %'s in the post.
I can make as many %'s in the initial post as I want and they are all fine. It is only after editing the post does the first % change to %.