Hasn't helped. So, I have determined through Mumble that people can see me talk instantly (but I don't see my chat) Also, I do /tp or /spawn etc and nothing happens locally. However, when I disconnect and then re-join, I appear in the tele location.
Having logged on at spawn, the pressure plates weren't responding. But I haven't been kicked from server yet after 30 seconds... so maybe it's syncing me up?