All material element 0 in static mesh missing (white) in Android AR

All the Speedtree static meshes look fine in the editor but once it’s built on Android ES3, the first material element in the material slots of an actor becomes white.

I have tried it on a simple cube. The material element 0 in the material slot just doesn’t work. So it’s not Speedtree problem.

It’s an AR built on Android.

Can anyone know what is the issue here?

Screenshot:

Solved. So there is a material overwrite in the BP_Placeable scene.