Child object shifts from the position of its parent biped bone when animation being imported to Unity

Some of our animators run into a strange issue.Some bones(biped) have c$$anonymous$$ldren objects on it(the c$$anonymous$$ldren objects do not have animation keys on themselves,they are individually purely linked to the parent),in some key frames these bones has big movements(like a fast wielding action).When exported to Unity,in the in-between time between key frames,the c$$anonymous$$ldren object sometimes s$$anonymous$$ft from the position of their parent,and becomes normal again when reac$$anonymous$$ng the next key frame point.

Why does t$$anonymous$$s happen?Would baking animation keys for every bone on every frame help with t$$anonymous$$s issue?

Thanks a lot!