Strict warning: Non-static method CRM_Core_BAO_UFGroup
First of all, this is not really an error that would cause you any damage, so I would not classify it as an important bug. The name is 'strict warning', which means that it is a warning (not an error!) that the programmer has sinned against the PHP rules when a strict check has been done. So it should be fixed at some stage, but these type of warnings will never disappear entirely as they do not break anything.

I assume you are now seeing those warning because you are a site admin? In most live sites 'normal' users will not see these warnings, but that needs to be configured in your CMS (Drupal, Joomla or Wordpress).