Clicking on a contact's cases tab gives Network Error Unable to reach the server
I'm pretty sure this was working very recently so tagging regression. Seems related to recent search changes since it uses force=1. Can reproduce on dmaster.demo.
Error: Call to undefined method CRM_Case_Form_Search::getGroupLabel() in CRM_Core_Form_Search->addContactSearchFields() (line 441 of .../CRM/Core/Form/Search.php).