Comment 32 for bug 57872

I'm still building and verifying, but I think the culprit is debian/patches/56-disable-session-save-on-shutdown.patch

@@ -865,9 +865,11 @@
        } else if (strcmp (action, ACTION_INTERACTIVE) == 0) {
                manager_explain_reason (manager, GPM_GRAPH_EVENT_NOTIFICATION,
                                        _("GNOME interactive logout"), reason);
+ /* This confuses too many people, so we commented it out
                gnome_client_request_save (gnome_master_client (),
                                           GNOME_SAVE_GLOBAL,
                                           TRUE, GNOME_INTERACT_ANY, FALSE, TRUE);
+ */

This hunk removes all action from the interactive branch, so all it does is log an interactive logout event to the information panel, but doesn't execute any action.