I am the organization admin for our Google Apps domain. I have the following pertinent settings configured:
External Sharing options for primary calendars - Share all information, but outsiders cannot change calendars
Internal Sharing options - Share all information
External Sharing options for secondary calendars - Share all information, but outsiders cannot change calendars
However, it seems nobody in my organization (not even myself) can share a calendar outside the organization more than just free/busy info. I'll add an external user with "See all event details" permissions, but they get reduced to only free/busy info when they're actually put on the ACL. There's a drop-down on their line, but none of the other options are there.
Is there something I'm missing? Why else might I not be able to share my full calendar details outside of my organization?