To reproduce:

1. Place the following content in the "Wiki Markup" editor:

   {html}
   <table border=0 cellpadding=0 cellspacing=0 width=700>
   <tr>
   <th width=200>Name</th>
   <th width=200>Email</th>
   </tr>
   <tr>
   <td>Admin</td>
   <td>
   {html}
   [mailto:jjones@mail.com]
   {html}
   </td>
   </tr></table>
   {html}
   

2. Save the content and you will be seeing an expected layout
3. Edit the page by switching to the "Rich Text" editor
4. Switching back the editor mode to "Wiki Markup" would lead to the following content being rendered:

   {html}
   <TABLE border="0" cellpadding="0" cellspacing="0" width="700">
   <TBODY><TR>
   <TH width="200">Name</TH>
   <TH width="200">Email</TH>
   </TR>
   <TR>
   <TD>Admin</TD>
   <TD>
   <DIV class="wikisrc">{html}</DIV>
   <P><SPAN class="nobr"><A href="mailto:jjones@mail.com" linktext="mailto:jjones@mail.com" linktype="raw" rel="nofollow">jjones@mail.com<SUP><IMG align="absmiddle" alt border="0" class="rendericon" height="12" src="http://localhost:8081/images/icons/mail_small.gif" width="13"></IMG></SUP></A></SPAN></P>
   <DIV class="wikisrc">
   {html}</DIV><DIV wysiwyg="macro:html">
   </DIV></TD>
   </TR></TBODY></TABLE>
   {html}
   

5. The layout is broken upon saving the page (see screenshot break.jpg)