When I check my blend shapes in iClone and Character creator, it works perfect.
As soon as I export these to 3DXchange or UE4 some of the blendshapes are not the same.
It seems to be the 4 blend shapes linked to the Jaw, Jaw_open seems to close from the side instead of opening?
Video for reference - https://www.youtube.com/watch?v=N6WOfmyraH4

Jaw open and eye rotation are bone controlled ( you have to rotate bones to set it )  ,  but you can export "Mouth open" as morph in the export settings.

This makes sense thanks for clarifying
Nothing else using ARkit I have tried in the past has worked this way before, the shapes have always included eye and jaw movement that correspond with the ARkit docs
I can make a custom blueprint to link both bone movement and the blendshape to correct this now I understand what's going on
Thanks for the help