With the new changes to Arah, in Path 3* if the npc (the salvari) doesn’t enter the room in which you fight lupi in then lupi randomly resets. This usually happens if you wipe after your first attempt to kill Lupi (the npc can be seen standing near the place where you kill the risen gorillas)
This happened about 3 times for our group and I submitted 3 very angry bug reports ingame.
If you get the NPC into the room she/he (still confused about the salvari’s gender) does not “randomly” reset and neither does, unless the person who holds the aggro steps in and out of the room (even shadow stepping will reset lupi)
p.s. If you bring the npc into the room, get him/her killed in P2 and don’t res him/her, don’t even attempt to do a 1/2 res, we saw lupi draining her HP to 0 even while he/she was dead.
p.p.s the NPC tanks about 2 ~ 3 AoE hits (hint for pugs)