Updated builds.

build/three.js

@@ -1836,7 +1836,7 @@
 		};
 
 		_proto.getNormalMatrix = function getNormalMatrix(matrix4) {
-			return this.setFromMatrix4(matrix4).copy(this).invert().transpose();
+			return this.setFromMatrix4(matrix4).invert().transpose();
 		};
 
 		_proto.transposeIntoArray = function transposeIntoArray(r) {

build/three.module.js

@@ -1191,7 +1191,7 @@ class Matrix3 {
 
 	getNormalMatrix( matrix4 ) {
 
-		return this.setFromMatrix4( matrix4 ).copy( this ).invert().transpose();
+		return this.setFromMatrix4( matrix4 ).invert().transpose();
 
 	}