A..... I........ You have to fix your boss AI. Atheon can still be pushed off. Templar can be pushed off. Every boss in every raid you ever make will have its movements exploited by players until you fix this. Players are crafty. They like easy rewards. They'll find a way. You need to fix the source, not throw a band-aid on one small part. Fix your boss AI so it's not terrified of grenades. Seal off boss rooms (make entry platforms despawn a la the jumping puzzle perhaps?). If you want to have a real raid boss encounter, you must be in control of the space the player can use. VoG shows enormous potential, but has a lot of very basic flaws.