Forgot to post this earlier, but we had 3 cases of friendly NPC aggro occur on BW a week ago, in all situations occurring after I pack flayered the NPC's target (twice on the LC tyrant, once on a bunch of chieftains in TA). Just wanted to give a heads up in case anyone noticed the same thing happening.
I've had it happen twice to me in isen mines with some random guard patrol and at south OP/COP the guards outside. I think instead of flayer its rather something to do with target forwarding through NPC's that causes it....tho it doesn't always happen so i'm not really sure on that but every time my defiler has had it happen its after i've used target forwarding.
This happened to me yesterday while I was running solo with my reaver. Not sure what triggered it but we were rolling a freep group out of TA and after the freeps were all dead I noticed I had two chieftans (troll and uruk) chasing me around TA lawn and definitely aggroed on me (via target's target display).
Freeps: r8 Mini
Creeps: r10 Reaver, r9 Warg, r8 WL, r8 Defiler, r7 Spider, r6 BA