I thought I had explained it very clearly. I do know that there may (but also may not) be different root causes. I am a programmer. It's obvious. Thus, it will be obvious to ANet's developers. I'm not here to deliver a step-by-step debugging routine, merely to report the existence of a bug. I did use the in-game reporting tool. I always do, but they cannot reply to it. It also does not have the potential to gain community support. It is common practice to use both the in-game tool and the forums. Here's a quick list of the top most recent reports. One has an identical description, two others are too vague but the end result is the same, and one has a bit more detail but not being one who does PvE, I can't comment as to those specifics. I simply used wiki to see when and where to go to complete achievements. There are many, and this is my last one. It's not rocket science, but obviously because I cannot DO the event, I do not know the specific steps in as much detail as someone who would have done it before. https://forum-en.gw2archive.eu/forum/support/bugs/Modniir-Ulgoth-Bugged (March 2017)"Even with all of the events completed, Camps taken over. Ulgoth event doesn’t happen. Timer just goes on then event “ends”. This has been the case all day today. Been trying to get it done for the Chuka collection, but haven’t been able to because of the bug." https://en-forum.guildwars2.com/discussion/23033/modniir-ulgoth-pre-event-bug (January 2018)"Pre event won't start, this is third day i've tried to kill ulgoth to get achievment for my chuka." https://en-forum.guildwars2.com/discussion/28463/modniir-ulgoth-pre-events-do-not-appear (February 2018)"2 times in a row i try this world boss for my chuka but both time i can't because ^ When i search the forum i see this bug has appear at least 1 month" https://en-forum.guildwars2.com/discussion/54993/bug-modniir-ulgoth (September 2018)"Zone: Harathi Hinterlands Bug: Captain Ganes and Lieutenant Lin are frozen at the end of Take the centaurs' forward camp, Can not progress to the next stage Take Bridgewatch Camp from the centaurs I have tried a few times today and a few maps, always the same." https://en-forum.guildwars2.com/discussion/72979/modniir-ulgoth-bug (Early April 2019)"The Seraph don't "dig in the forward camps", during the phase where we are meant to proceed to "push back" the centaurs never spawn and charge. This has happened the last 4 days to myself and many others on my server during the Modniir events around 8pm-4am Australian time, I'd heard of players beating him about 2-3 days ago but I haven't heard of any cases since." https://en-forum.guildwars2.com/discussion/74330/bug-modniir-ulgoth-cant-be-killed (Late April 2019)"Hey, I just wanted to say that there is a bug on Modniir Ulgoth, he stays invincible, so we can't kill him, Atm, this event is part of Chuka & Champawat Collection Number 4, in "Tiger training Guide" So if you could fix that it would be super cool I sent a /bug with screenshot with the ingame tool, just in case, thanks" And, of course, now.