Confirming the exact same error, using UE5 release build and freshly generated metahumans with a blueprint project.
In the Editor, everything runs fine and smooth.
But in a cooked / packaged program, the very exact same Error ( Assertion failed: SchemaIt != SchemaEnd, etc.) appears in the crash.
Even after completely deleting all anim/pose files from the metahumans directories and re-cooking, i still got the same issue.
The only way to solve it for me seemed to be to delete all Quixel-Bridge imported metahumans out of all levels / Scenes, then the project does not crash anymore. Kinda… unpractical. 
I’ll re-implement the Metahumans and try manually removing LiveLink nodes from the FaceAnim. Let’s see if that does the trick here as well 
Edit: I edited Face_Anim_BP in the common folder under Metahumans. Sadly, it did not work. Still crashes with UnversionedPropertySerialisation. Maybe there are other blueprints or animation blueprints that link to livelink, but i’m just an UE5 Beginner. Both Metahumans i imported don’t seem to have an own Face_Anim_BP.
Guess i’m back to the mannequin til the next patch 