Light is going through plain objects

I made this topic because a have some trouble when importing .obj in Unreal Engine 5. I using Mineways ( to export Minecraft maps to .obj objet. No problem during the importation and applying the texure. But the light behaviour is not like other objects. I made two screenshot, a lit and unlit version to explain my issue. The model on the left is a basic composition of 5 cubes. We can see that there is no light coming from SunSky. But the model on the right is the Mineways importation, and there is light coming from nowhere.

What I check:

My only concern is about the size of the .obj. Mineways export models in low sizes, so just after the import I scale up the model by 100. I don’t know if this is a problem for the light computation.

Thanks a lot for any anwser :smiley: