so it probably means that you are logging in backend with a different domain/www prefix. Metainfo are associated to each link, if links change metainfo change too.
If you specify metainfo for http://www.mysite.com/
and open http://mysite.com/
without www prefix they won't apply, it's a different link.
The same happens if you had links without SEF rewriting http://www.mysite.com/index.php/mypage.html
and change them to http://www.mysite.com/mypage.html
activating the Joomla SEF rewriting.
The same happens if you change links for https starting with http://www.mysite.com/index.php/mypage.html
and change them to https://www.mysite.com/mypage.html
Every time a link changes the meta data associations is lost. Keep in mind that the URL is the unique identifier for meta data.