Keystone BasePage History Inheritance Error

KeystoneBasePageHistoryInheritance

var keystone = require('keystone');

var BasePage = new keystone.List('BasePage', {
	map: { name: 'title' },
	autokey: { path: 'slug', from: 'title', unique: true },
	history: true //<=== This is the single change from the example in the docs.
});
BasePage.add({
	title: { type: String, required: true },
	slug: { type: String, readonly: true },
});
BasePage.register();

var ChildPage = new keystone.List('ChildPage', { inherits: BasePage });
//ChildPage.add({ child_content: { type: String, readonly: true } }); -- This is not needed to reproduce the bug
ChildPage.register();