Visage texture has disappeared

RANDYL

Hello, I have created some characters with Victoria 8 base. I made changes using Genesis 8 Female body morphs, and alikes, then I finished by using Skin Builder 8.

I used half a dozen of these characters in different scenes (I open the scenes, then merge the characters in), and after about a hundred renders, one of the characters lost the texture from its face (see image below). It happens in every file : in the scenes, and also in the original file where it was created. What is strange is that it only happened on this one, and not the others (all of them were made using the same method).

I think it happened after using ctrl-z to undo a posing action.

I have no clue on how to restore it, and even to prevent this from happening again.

Has any of you encountered the same problem and/or have an idea to help me resolve it?

Thank you very much for your attention and your help!!!