When the default home page for users is set to "My Moodle", the "Turn Editing On" link on the front page redirects to the My Moodle page instead of turning editing on. The only workaround I've found is to set the default home page back to "Site", make the edited and then return the setting back to "My Moodle". Unfortunately, this will mean the site will work differently when an administrator is editing the front page--not a good result.