TYPO3 Exception 1195126772

$toolbarItem must implement interface TYPO3\CMS\Backend\Toolbar\ToolbarItemHookInterface

  1. Check whether the requested class really implements TYPO3\\CMS\\Backend\\Toolbar\\ToolbarItemHookInterface

Exception on shortcut

  1. The error might have been caused because the argument to the constructor was not passed by reference as requested by the Interface/Class. In general this causes just a warning but can also lead to serious problems.
  2. There's a bug in PHP 5.5.6+ which causes this Exception: https://forge.typo3.org/issues/53682