Metahuman head hidden face map texture not working

When I use a Wardrobe Item that applies a Head Hidden Face Map, it works fine within the MetaHuman Creator. But once I assemble the character, the Head Hidden Face Map seems to be completely ignored, while the Body Hidden Face Map works everytime. I’m using 5.7 and I can’t find anything on this issue… besides turning off Substrate and Virtual Textures in the Project Settings, which did nothing.

Has anyone seen this?