https://downdetector.com/status/level3/map/

Heck this site tends to be reliable when Optimum goes down, judging by the map it would appear they are having issues across the US which could be causing issues with the way the information is being sent and could explain why the lag is so sporadic.

Earlier in a dungeon 2 players d/ced and never came back, then the other d/ced and finally I d/ced, but before that we all had the DC mark but then the rate at which we disappeared honestly doesn't tie into the servers themselves but how the data was being lost. The two players had their data lost the most so they were later booted while me and the remaining player waited, while it appeared stable we soon lost our own packets and were d/ced.