When you export from unreal, in the export settings do you have the export morph targets box checked, this should be unchecked, then convert using the FBX converter
I checked EXPORT MORPH TARGET otherwise the shape keys are missing.
I tried exporting it again with it unchecked and re-import. On blender the shape keys are missing. And when I import back to Unreal. It has the same issue. HERE
I noticed the vertices count changes from the original. Not sure if that’s why and if this is fixable Comparisson
and when making edits on the face mesh in blender do you have the basis shape key selected in the shape keys.
Yup I did it on the basis
Also in the import to unreal are you selecting the face skeleton rather than the metahuman skeleton?
I created an own skeleton (based on the face rig), and re-target the blueprint to the new skeleton
I also tried just using the original skeleton. Both works but still have the same issue.