We do get there unfortunately. In `getChildNodename` there is a branch of logic around whether or not a mapped nodename exists, and since we do have a mapped nodename in this case, it bypasses the ID generator entirely and just returns the name.

Code is:

```php
        $childClass = $this->dm->getClassMetadata(get_class($child));
        if ($childClass->nodename && $childClass->reflFields[$childClass->nodename]->getValue($child)) {
            $nodename = $childClass->reflFields[$childClass->nodename]->getValue($child);
        } else {
...
        }

        return $nodename;
```