1.4 disappearing bosses

On my server I have heard of at least 5 raid bosses on my server (34) disappearing after update. I received my boss after update went live in holy ruins and now it is nowhere to be found. Many other players are experiencing the same issue. The bosses were already disappearing randomly before, now it's worse. This needs to be fixed.

I had the announcemnt that a boss has arrived, and went to go fight it a few hours later, and it was gone.