When a hub feature is created, there are two steps: (a) creating the subpage and (b) "transcluding" it on the hub. However, because the second step happens first, the cache is saved referring to a non-existent subpage, with a subpage created immediately after. This leads to a confusing interface.
Since users can do step (b) by hand and *then* create the feature, I think the system should consistently purge cache when new features are created to avoid the confusion.