Material appears black the first time mobile game opens

I have a floor material that refuses to render properly the first time the game opens, and appears black. If you go back to the main menu and reopen the main level, it shows correctly.

The floor is a static mesh. A scaled cube that is above 0 on the z axis.
The black material persists no matter how long you wait.
I have tried changing the material. Not working.
I have tried changing the mesh. Not working.
I tried using the material in a loading screen before the main level. It renders fine in the loading screen, but appears black again later.
There is no lighting in the scene, and every material is unlit.
Mobile hdr doesn’t have an effect on it.
The material looks fine always on pc and in the standalone mobile mode of the editor. This problem only happens on mobile.

I would appreciate some help to make the material render correctly! I have spent weeks trying to solve this.