How do I unlock this World Event?

I'm trying to 100% my content book. All quests, discoveries, etc. The very last thing I need to do is this single world event "Risen Return." But it has refused to show up for the past few days, so I assume it's locked behind something. All I know is that this is tied to the grave digger quest according to the wiki which I already did. Is there a hidden requirement or something?

 

I’m pretty sure you just gotta get lucky