aye, that they do.
on a side note they do not see invis, however it appears that if Engineer Tristos is up and someone is aggro'd by one of these, he can somehow warp directly to the flame and begin attacking.
Been killed by him in both the UPPER and the LOWER safe rooms in the tower. In the upper, someone trained in a see invis ( my toons had perma invis on ) and once the see invis mob broke invis, flame aggro'd then Tristos was suddenly there killing at leasure. In the lower safe room, suddenly he was just there and as he started to attack ( breaking invis ) flame was also there and aggro'd.