diff --git a/test/unit/property-effects.html b/test/unit/property-effects.html
index c9c3c1355a..c1be29da2d 100644
--- a/test/unit/property-effects.html
+++ b/test/unit/property-effects.html
@@ -1621,27 +1621,33 @@
         this.observer = sinon.spy();
       }
     }
-    TestClass.createMethodObserver('observer(a, b.c)');
+    TestClass.createMethodObserver('observer(a, b.c)', true);
     customElements.define('pe-method-observer', TestClass);
     let el = document.createElement('pe-method-observer');
     document.body.appendChild(el);
-    assert.equal(el.observer.callCount, 0);
-    assert.equal(el.pcSpy.callCount, 0);
-    el.a = 'a';
     assert.equal(el.observer.callCount, 1);
-    assert.deepEqual(el.observer.getCall(0).args, ['a', undefined]);
+    assert.deepEqual(el.observer.getCall(0).args, [undefined, undefined]);
     assert.equal(el.pcSpy.callCount, 1);
-    el.b = {c: 'c'};
+    el.a = 'a';
     assert.equal(el.observer.callCount, 2);
-    assert.deepEqual(el.observer.getCall(1).args, ['a', 'c']);
+    assert.deepEqual(el.observer.getCall(1).args, ['a', undefined]);
     assert.equal(el.pcSpy.callCount, 2);
+    el.b = {c: 'c'};
+    assert.equal(el.observer.callCount, 3);
+    assert.deepEqual(el.observer.getCall(2).args, ['a', 'c']);
+    assert.equal(el.pcSpy.callCount, 3);
     el.setProperties({
       a: 'A',
       b: {c: 'C'}
     })
-    assert.equal(el.observer.callCount, 3);
-    assert.deepEqual(el.observer.getCall(2).args, ['A', 'C']);
-    assert.equal(el.pcSpy.callCount, 3);
+    assert.equal(el.observer.callCount, 4);
+    assert.deepEqual(el.observer.getCall(3).args, ['A', 'C']);
+    assert.equal(el.pcSpy.callCount, 4);
+
+    el.observer = sinon.spy();
+    assert.equal(el.observer.callCount, 1);
+    assert.deepEqual(el.observer.getCall(0).args, ['A', 'C']);
+    assert.equal(el.pcSpy.callCount, 5);
     document.body.removeChild(el);
   });