there is a bug in
/components/com_virtuemart/views/user/tmpl/edit_address_userfields.php
something about the fieldsets/tables does break the HTML (and firefox does show that red in the site sourcecode, other brower seems not that intelligent)
<table class="adminForm user-details">
...
<fieldset class="userFields">
<span class="userfields_info">Text</span>
</table>
</fieldset>
for short it does
Quote<table><fieldset><span>Text</span></table></fieldset>
and browser should/does not know how to interpret that (validator.w3.org does crash while trying to parse it)
which makes it for me as webdeveloper even more complicated to style pages with css because elements does jump out of the line.
the bad thing is that this was introduced 15.08.2013 and no one seems to notice it.