It looks like the whole skeleton is marginally different.
All of the translations seem marginally off.
Are you sure the initial retargeting pose is an exact rotational match (Same identical rotations to the original on all bones)?
Regardless of that. It looks like the forward arm of the frame you screenshotted is hooked to a different bone or not properly retargeting.
The correct position of the clavicle should match up with the original version.
Distortion is off going forward in the chain but it’s always somewhat accurate at the base.