The mailman3 list server was offline the past week, due to troubles it had delivering email to administrative user accounts. This generated excessive error logging to disk. I'm not 100% sure this is root caused but after clearing the queue it seems to be running happily again. I'll try and keep a closer eye on it. Bryce P.S. there's still a problem with some people unable to subscribe to the mailing lists; I doubt this change will fix chat, so this problem is still on the todo list.