Hosting 'features' fail to enable dependencies

In hosting_civicrm, we have an API module that does not itself expose a Hosting 'feature', but is rather a dependency of its sub-modules. When enabling one of these submodules via Aegir 'Features' page, the dependent module is not enabled.

From what I can tell, all Hosting 'features' in core depend only on core functionality that is enabled on install, so I guess this hasn't been exercised much before.