In Duty Finder, WHM should be saving Shroud for the sisters so that the offtank can easily establish hate. WHM should NEVER throw regen on a tank when sisters are about to pop -- they will be blinking red before the offtank can even touch the red sister (if the red sister spawns far away from the group). I'm not saying it's your healer's fault... but it is usually a combination of players causing an issue to happen. There's a lot of give and take with enmity in this fight. DPS should also be careful not to get hit by unnecessary AoEs. (Both sisters will AoE, as well as Garuda herself.) The more dps get hit = the more the healer has to AoE spam = the more hate the healer is going to pull from the tank. As always, dps should be careful not to attack something BEFORE the tank/offtank pick it up just in case they pull hate and require extra healing.