There seems to be an issue when integrating custom metahumans into the project - specifically around LOD 0 and on certain platforms (PC and Android) in “Performance” mode.
Problem: The head snaps off the body and remains static while the rest of the body animates in the above settings. There is a strange texture applied to the bust as well in this static position.
Additional Notes: Heads here were integrated via MetaPipe and another with MeshMorpher, in order to maintain the sculpted mesh. Forcing the next LOD down seems to solve the problem, but acts as a non-ideal solution as we lose the extra finesse and detail in the original mesh.