PHP Fatal error: Cannot redeclare class Twenty_Fourteen_Ephemera_Widget

We are running a Multisite installation of WordPress. This morning, I began updating all of the WordPress themes (2010, 2011, 2012, etc…). I installed the latest version of Twenty Fourteen (1.2) and created a new test site. As an admin, I went to Appearance > Themes where another site is selected as the “default” theme. I then selected the Live Preview button on the twentyfourteen theme and received a blank screen which generated the following fatal error:

PHP Fatal error: Cannot redeclare class Twenty_Fourteen_Ephemera_Widget in \wp-content\themes\twentyfourteen\inc\widgets.php on line 269

Has anyone else received this error?