In 2.7, with the Shared Items plugin installed, opening up a link and trying to save it with the "Update Link" button sends you to a "WordPress Failure Notice" page with the following text:
Are you sure you want to do this?
Please try again. (link with href='/wp-admin/link.php?action=edit#038;link_id=68')
Deactivate the plugin and it saves Links like normal.