Can not override animation clip in timeline?

I downloaded some animation clips from Mixamo and find something wrong (like this picture, I think angles of sword and hand are wrong, it may turn like 30 degrees left)
However, though I tried to use record mode and override keyframe, I found there is no any changing on these animation clip. even though I double-clicked animation clip and try to modified animation data, NOT USE.

I don't know what's wrong about it.

 

Hello,

I'm honestly not 100% sure this is the issue, but from what I've noticed when using the timeline myself, it appears as though timeline clips only override keyframes, not the entire clip itself. So if you have an idle animation playing in the timeline, and a running animation in the animator, you're going to get a cross between the two since they likely don't have the same bones keyframed.

What I've done to work around this is play an empty state in the animator while the timeline is playing. This way, there is nothing playing in the animator that could be messing with the timeline's animations.