Dagath's Doom will steal kills from your weapons, preventing on kill triggers, such as from weapon arcanes, galvanized mods and similar. The duplicated damage from Doom will trigger as soon as it's enough to kill the enemy, meaning unless you kill the enemy in one shot at the moment Doom would trigger, your weapon can't get on kill triggers. One solution to this would be making the damage from Doom count as damage from the last weapon that supplied damage to it.