Discourse offers the feature of inviting new users to an instance via email. These emails can contain automatic access to any closed group. They also provide a way to track which users are bringing in participation to the forum.
These invitations are incompatible with the Wikimedia Login. Invitations via email are coupled with the ability to create local accounts, which must be disabled in order for the SUL to work.
We will commission additional work to the Wikimedia Login to allow for these invitations to be re-enabled.