Unexpected and sporadic rotations after export.

I start by recording motion capture with Rokoko, and the animation is clean. I import it into Unity, set it to humanoid, and then bring it into UMotion for adjustments.When imported, I get these very sporadic leg movements, like jittering. Even if I remove the bad keyframes from those legs and export it again,

the UMotion editor looks fine, but the export is still just as jittery.

In the video, you can see there's no jitter in UMotion, but a lot of jitter in the legs after export.

I'm going insane because I then have to re-import the animation, remove the keyframes again, and export it. It's really slowing down my workflow. Please help!

Let me know if you'd like to make any more tweaks!