Well we ran a little Deathwyrm last night on EN only all was well and good - got to Gravity, triggered all the spots - phylactery down and then we start moving to the end to loot and leave when WHAM Lag - full lockup - nobody moving - still have voice chat and everyone confirms they have it.....we wait a few minutes then decide to have a few of us log to hopefully releash the lag monster. It took me 30minutes to get back in - 2 reboots, router reset, flushdns (I think that did the trick in the end).
So umm about those performance improvements in the latest patch......looks like there is more work to do.
I will point out that we had an oddity in that most of us were in the same general area (ie. everyone came back to the south gravity lever at about the same time and we all dropped to the lower left to make our way out as we made the first right turn someone who was a bit ahead asked for gravity to be off and as we hit the spikes the lag monster hit......so it could be something similar to the Kludarj guard proc lag....but it is different from that in that we couldn't stop hitting the spikes since we were stuck in them - I lost about 400 HP before I logged out just ticking the spikes over a few minutes.
It was bug reported last night but I thought I would provide a bit more detail here and also see if others had any similar results since yesterdays patch.