Just a question : are you sure that you have that url inside the email body ?
if, inside your email, you move the mouse over the link above and right-click , and you click on the context menu item "copy link location", and after you paste it somewhere (notepad or browser address bar), do you have the url with the # part ?
I ask it to you since I do not think that the fragments (# part of the url) are sent to the server, since they should be "commands" for the browser if I'm not wrong.
So the # part of the url should not arrive to Apache's mod-rewrite ....