animation retargeted from ue5 manny to pmx model is not on the ground

[zaichenhu]

I have used vrm4u to import the pmx model to ue5, and retarget animation using RTG_ManneQuin, in the retargeting editor, it displays right, but when I exported it as a single animation sequence, the animation of pmx model can't lock on the ground. Below are printscreens for comparision in the same frame.

[zaichenhu]

clip to floor is normal for this animation. I have used .vrm model for testing, it didn't occur this problem. but pmx models do.