Animation “Hit” not play correctly

[QiYi627]

When i use “animator.Play("Hit") ” ,the animation doesnot play correctly in play mode.The "ArmR[1]" in path "Dummy/Animation/Body/Upper/ArmR[1]" auto rotate to 0 from 45 and "ArmR[2]" disappear.But when I play the animation in animation editor ,the animation play correctly.Is my code wrong? How can I play the animation correctly in play mode. Thanks. The version of my unity is 2018.3.0b7