Currently Confluence display it's URL in full ASCII format. When special character is included in the URL, sometimes, this character is not properly recognize in the URL when send in the mail.

For example

1. Create a new page
2. Add a heading in the page "test?"
3. Add there the toc macro.
4. Copy that URL, and send it through email to someone else.
5. That person clicks on the URL, the wiki page opens, but does not direct to the correct heading. You will notice the '?' character is not considered as a part of the URL:
   

However this could be mitigated if the URL is encoded in the following format. <confluence-URL>/display/VM/TEST#TEST%3F

This can be rather inconvience for user who wish to send Confluence URL in a mail.