Sidebar updates immediately on new access. When a member joined a group themselves, or was added by an admin while already logged in, the group/subgroup list in the sidebar previously stayed stale until a full page reload. It now refreshes automatically the moment access is granted.
No self-notification on group @mentions. Mentioning your own group's handle in a comment or thread no longer sends you a notification or email about your own mention, matching how individual @mentions already work.