Sometimes when you set a pose to the 3jnt leg, and playing with the ‘Full 3 bones IK’ attribute,
the ‘legBack_L0_roll_ctl’ take a rotation of 180 with a blend value of 0.5
Apparently, the problem appears only on the left side and it depends on the bind pose.
Unless I’m mistaken, the solution seems to be to make a world match between these 2 groups:
‘legBack_L0_ik2B_A_ref’ & ‘legBack_L0_ik2B_B_ref’.
It’s not a blocking problem, we just need to add a small ‘post custom step’ procedure.
I hope this will help.