Like, with Eureka, it's a serious problem within Eureka. With the way the game handles things, if there's a full instance of people in Eureka, you're lucky if you can even SEE the Notorious Monsters. It's a big enough problem to be able to damage the monster when you can't see it, but I've had instances where I can see the monster, but not the AoE indicators for some attacks.

Monster should take 100% priority on what is shown on screen at all times. Followed by your party members, then NPCs, then other players.