Intermittent Partner Album Sharing

I'm having a heck of a time troubleshooting album sharing. I've shared multiple albums with another user, and they are not populating in their Immich iOS app at all. Their screen just says "Empty List". I'm not even sure where to start. We do have each other selected as partners. If I log into their immich account on the web, they are all there, but they just aren't populating in the immich app.