I started recording video as soon as I went into the quest last night in hopes to capture what people have been talking about to bug report it; so of course everything ran smooth for me without lag.
This has been my experience as well; unable to replicate. Which is annoying.
I suspect there's an entirely different issue that's causing the problem, but without knowing all the variables, it'll be hard to track.
Personal suspect would be
1. Display issue. We don't know what each user is running thier DDO client under, whether it is Windowed, Windowed Full Screen, or Full Screen. But an OS like Windows has background draw functionalities as well that remains on under certain ways of running stuff. If a user is running DDO on bare bones to get as much FPS as possible, but Windows 10 or 11 for example is trying to draw something in the background of the desktop with more advanced functionality, there could be a conflict that causes the lesser priority service (DDO) to be terminated rather than Windows falling over itself. DDO is old enough where it could have conflicts with it.
There's ways to disable and prevent the OS like Windows from using such features, but it varies by display device and what account previleges you have, so there's no simple way to show how to do that to test.
2. Insufficient storage. One very common isssue is users overload their storage drives. This is fine if there's nothing else going on behind the scenes and you have enough RAM as well, but if Windows is attempting to do something silently behind the scenes and there's not enough storage, things can again topple over. Or of course, if DDO ends up needing to swap anything out of memory to a page file, and there's insufficient space, DDO can again topple over.
This could have a sub issue where if sudden change of many enemies and uses more resources that the system doesn't have on hand, then also another reason to crash and topple.
3. Driver issue. Out of date drivers that haven't had their "issues" patched up yet is on the system and so when DDO calls up something, performance drops hard then crashes. And incidentally, sometimes an updated driver has something patched out, causing problems too.
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It's unlikely to be purely a network issue, since it should be replicatable more easily at that point with 1-6 players who are in contact with each other and observing their systems (different network locations). Or on my single / multi-box runs (same network location).
But each of the ones above have enough variation where diagnosing is not a simple matter.
J1NG