The arm_ms_2jnt_01 component arm_L0_ik_ctl cannot make the palm rotate. When switching to ik control, you need to use arm_L0_fk2_ctl to adjust the palm rotation posture. I don’t know if it is a component error or an expected setting. I tried to fix it myself, but it hasn’t worked so far. I searched for related issues of this component in the forum, and no one else asked, so I posted for help.
maya:2018.4
mgear:3.6.0
Thank you!