got disc priest in your group?
I've seen Laser Matrix pull mobs that were in combat with other mobs, but not yourself. For instance the long pathway in Shattered Hall (since we had TBC timewalking this week) where there are Gladiators fighting each other.
I've never seen it pull a group that was completely out of combat.
My guess is someone in your group simply mistargetted and accidentally pulled the group instead of the boss, possibly without realizing.
i've done multiple freehold keys this week and none have pulled that pack. i think someone in your group may have accidentally pulled
Willing to bet was one of your mates.