Fix #7922

materialsLibrary/src/mix/mixMaterial.ts

@@ -132,7 +132,6 @@ export class MixMaterial extends PushMaterial {
     @expandToProperty("_markAllSubMeshesAsLightsDirty")
     public maxSimultaneousLights: number;
 
-
     constructor(name: string, scene: Scene) {
         super(name, scene);
     }

src/Materials/Background/backgroundMaterial.ts

@@ -665,7 +665,7 @@ export class BackgroundMaterial extends PushMaterial {
 
         var scene = this.getScene();
         var defines = <BackgroundMaterialDefines>subMesh._materialDefines;
-        
+
         if (this._isReadyForSubMesh(subMesh)) {
             return true;
         }

src/Materials/pushMaterial.ts

@@ -55,7 +55,6 @@ export class PushMaterial extends Material {
         return false;
     }
 
-
     /**
     * Binds the given world matrix to the active effect
     *

src/Meshes/mesh.ts

@@ -2814,6 +2814,8 @@ export class Mesh extends AbstractMesh implements IGetSetVerticesData {
      * @returns a new InstancedMesh
      */
     public createInstance(name: string): InstancedMesh {
+        this.makeGeometryUnique();
+
         return Mesh._instancedMeshFactory(name, this);
     }