Ajax error: Call to undefined function node_form_validate()

Was unable to use AJAX on node/add forms while using the group module when trying to add a node to a group at group/xx/node/add/nodetype; kept getting a "Call to undefined function node_form_validate()" error. Traced it back to this module.

Once I added require_once(DRUPAL_ROOT . "/modules/node/node.pages.inc"); at the top of inline_entity_form.module, the error stopped happening and everything worked correctly. I know that's not the proper way to do it, thus the bug report.