Got an exception without that null, think it's just the first entry in `page.yml` with the empty name and parent so the path is `/cms/simple` which exists for sure, the exception:

```
  [Doctrine\ODM\PHPCR\Exception\InvalidArgumentException]                                                                                                         
  Detached document or new document with already existing id passed to persist(): Cmf\MainBundle\Document\SeoPage@000000005b3d19fe0000000053b79f12 (/cms/simple) 
```