I also saw the ugly background now in some of my mails and in some email clients, results were also different by browser; so gmail in chrome was ok but not in IE. Got rid of it by removing <tbody> tags and generally porting the html back to the nineties, make your html as old as possible and it should work.
<div><br></div><div>There is also interesting information about what is supported of html in emails in&nbsp;</div><div><a href="http://www.campaignmonitor.com/css/">http://www.campaignmonitor.com/css/</a><br></div><div><br></div>
<div>Hans</div>