#ubuntu has 1300-odd members. On joining the channel, there's a 5-second gap between emitting MembersChanged for yourself and MembersChanged for all those members. At a guess: <daf> perhaps idle is doing g_slist_append 700 times or something
Olli says that a 5 second lag from the server for the initial user list is normal, and that he's profiled this extensively.
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.