I found ue4’s root motion doesn’t work well when character doesn’t have root bone. And the sample characters on mixamo(free) don’t have it.
Adding root bone is not hard work, but user have to upload their modifed character to mixamo and buy the animation… Uploading means user have to spend auto-rig count.
So, It was about mixamo’s support issue. I tested the Fuse character, which has root bone and supports unlimited auto rig, And its root motion works well.
I hope it helps anyone has the same problem.
( sorry for my short english. If you don’t understand something, feel free to reply.