DataTransfer is not set.

Problem/Motivation

After updating to 7.x-1.5 I get an error when pasting into wysiwyg + ckeditor.
Uncaught TypeError: Cannot read property 'getData' of undefined
#2552809: [legacy ckeditor plugin] ckeditor 4.5.x compatibility introduced a paste check and the dataTransfer isn't set for me.

      // Prevent paste, so the new clipboard plugin will not double insert the Atom.
      editor.on('paste', function (evt) {
        if (Drupal.dnd.sas2array(evt.data.dataTransfer.getData('Text'))) {
          return false;
        }
      });

Should we check if dataTransfer is set first? Or is something misconfigured on my end?