Thinking back on it there was a strange event earlier in the evening (and seemingly unrelated) where I typed two lines of text and they had a delay in appearing. When they finally did, 2-3 seconds lat
Happened to me also when I was in a boss fight with about 50 other people for a quest. I think it has to do with people in your area and what they are doing also.
Lag. Packets were trying to get through during lag. One the lag stopped, the all pinged the server at once. That caused the server to freak out and boot you