Hi,
When you access the order from the email, the system has no idea that you want to go to the profile of CB when you click on the back button. So no it's not "as it should", but "as you would like".
That's why I told you:
If you want to force that URL, you can edit the file "show" of the view "order" via the menu Display>Views and change the line:
<input type="hidden" name="cancel_url" value="<?php echo JRequest::getString('cancel_url'); ?>" />
So that way, you can force the URL you want for the back button, so that it always redirect to the CB profile, regardless of where you accessed the order from.