Regine_EAMythic;
Shadow Fiends looting players and leaving no corpse is working as designed since the inception of Khaldun years ago. Because it's not a common behavior, it was specifically mentioned in the notes as a fair heads up. Losing potions, bandages and reagents is part of the risk and difficulty of these monsters. Not losing your equipment is simply standard player responsibility: insure you gear, make sure you have sufficient funds in the bank and do not wear cursed artifacts when fighting them.
So be sure to not wear cursed items and keep your stuff insured during this quest, if you need insurance gold then talk to an elder for help.
KD we might wish to put emergency funds available to trusting elders to help people, PAS/Alliance, with insurance needs.