Guild Wars 2

I don’t know what is causing it, but in the molten facility when you reach the boss room sometimes the “Weapon Test” sequence doesn’t trigger which forces us to restart the fractal. We tried various things like wiping, killing the npcs etc. but nothing helped.
This happened three times to me now.

Have someone lead the NPC’s in and stay with them through their dialogue. It bugs out when everyone runs into the room and the NPC’s stop to do their dialogue but no PC is by them.