A while back there was a topic about mysterious, staggered 4 hit attacks that sometimes happened in PvP. I can't find the old thread so not sure if it was resolved, but I do recall there were questions about whether it had been captured on video. The below shows it at about 4:30. Apologies if this was already cleared up, but thought it was interesting
https://www.youtube.com/watch?v=SKc6YRsgU8Y
https://www.youtube.com/watch?v=SKc6YRsgU8Y