The commands that manipulate meta data leave behind stale object caches.

I noticed this here: #158 (comment)

Basically, the add_metadata() call does not include the additional cache-busting call that add_site_meta() includes. The same problem applies for all add, update and delete calls on meta objects.

Most pragmatic solution:
Provide a default mapping of CRUD function in the base object that can be optionally overridden in the specific meta commands.