Control Rig - Basic IK messing up mesh


I am trying to put Basic IK on legs of my character. The IKs worked pretty well on the arm, with only minor twisting, but the legs are all over the place when I execute the Basic IK.

I’m not sure where I’m going wrong. Does anyone know why this would be happening or have any good resources that could help?

Having the same issue and its different depending on engine version but still there. Did you find any solution?