Every Radiance Instance has an exploit(s):

DD - fighting at the doors, plus many others
GS - The Hunter on the Ledge for the final boss. The archers on the other side of the gate. Many more..
Skum - The heavy armor activates boss/Hunter Arrow door pull
Forges - The edge of the cave entrance fight on the final boss away from the fire.
16th - The Mini up on the cliff, bugging the bugs
FG - all kinds of stuff, including dropping group, running and getting killed out side the final boss door and the disguised mini rezing everyone."