Verified with a few people the issue is if you are zoning on win you get skipped on the win and lockout.
This is a longstanding issue and not specific to any event. It can happen with any raid or group task. If a player is zoning during completion, there's a chance they will not receive credit. Interestingly, there was an attempt to fix a bug like this with the September 19, 2012 game update:
Yes have seen it happen in the past on occasion. But the person was still able to loot an item in the chest.
Happened today. Died on Allayna. No lockout for the event, someone zone an alt for loot and received the lockout (intended) but received Allayna's coin. Allayna could not loot anything since the toon received no lockout from being dead. Can look at that toon if you want to try to reproduce it.
in our case they werent zoning, just dead. but had no way to apply the lockout so ended up giving to someone else.
If anyone could give us Server, Date, Time, Event, and the names of the affected characters, we might be able to look further into this.
[Sun May 03 19:06:24 2020] That was the last death I see in logs before the win. Xegony, May 03, 1906, Vindicator, Allayna and Elysa.