I’ve had no less then 4 very good groups for it and we’ve lost at the end every time. This is with all defenses up and everyone doing what they should be. The problem seems to be with having extremely difficult mobs spawn just steps away from the core itself and 2 of them at once. When they spawn you have to focus fire them, but they still take a lot of damage and time to take down. While this is happening, other mobs slip in from the sides and damage the core. Sometimes even the difficult mobs walk right up and damage the core also.
This happens several times during the fight and that results in the core being destroyed and us failing the mission. I’ve been trying to get passed it for 5 days now and am still trying.
It needs to be toned down on normal difficulty because right now it feels more like advanced then normal.