[2021] Archon Boreal Despawned and I cannot progress.

Hello do you happen to have any screenshots or videos of the fight so we can see exactly what happened? If you can provide some more details then we can look into it further.

You should be able to attach it to your post if you drag it onto the editor. Try that maybe?

8 minutes ago, hodagacz said:

I had restarted twice and was ducking back in the entry tunnel to avoid her lightning when all of a sudden Boreal stopped shooting. I run out to find them and circled the arena. Their health bar was still on the screen but the boss is nowhere to be found.

Can you send me your EE log file if you are able to? You can access it by going to your launcher and selecting Settings (gear wheel) then "Get Logs"