Blank page with saving non-published revisions with IPE

This happens with panopoly's version of 7.x.3.x-rc1 and with 7.x.3.x-dev (with http://drupal.org/node/1798294 applied). Click save, the page is blank until refresh, none of the changes have been saved.

With RC1, you get a series of notices of the form:

Notice: Undefined index: 1108 in panels_edit_display_form_submit() (line 162 profiles/panopoly/modules/contrib/panels/includes/display-edit.inc)

With 7.x.3.x-dev you get those same notices, plus:

Notice: Undefined offset: 2 in panelizer_panels_cache_get() (line 1057 of /panelizer/panelizer.module).

Which derives from the changes introduced in the patch here: http://drupal.org/node/1798294#comment-6888594

list($entity_id, $view_mode, $vid) = explode(':', $key);