Fix matrix interpolation issue

src/babylon.scene.ts

@@ -2743,6 +2743,10 @@
                 currentPosition.scaleAndAddToRef(scale, finalPosition);
             }  
             
+            if (!originalAnimation._workValue) {
+                originalAnimation._workValue = Matrix.Identity();
+            }
+
             Matrix.ComposeToRef(finalScaling, finalQuaternion, finalPosition, originalAnimation._workValue);
             return originalAnimation._workValue;
         }