I figured out that most of the problems with the shaders were coming from the MaterialFunction MF_CharacterEffects.
It is one of the last node in most materials. You can just bypass them if you don’t need some of the effects (I think there are some Rimlight effects and despawn stylization done there).
I will inspect further more the issue and what configuration needs to be done in the project to use this material function but for now I don’t need it.
Here is an exemple with the redBuff minion:
