When a newly created content is previewed, it isn't published yet, and therefore doesn't have a location yet.

The Preview Controller partially covers this by creating a fake location, with a draft flag, ($location.isDraft in twig, that has some of the properties of the future location, like the parent location id.

However, in some cases, like a link to self, one may use the location id, and get an error. This should be documented.

Note that using path(location) might provide a better experience, but it should be tested.

Adding some BDD coverage about preview/draft templating might be a good idea.