fix(runtime-dom): fix anchor loss caused by unmount

packages/runtime-core/__tests__/components/Teleport.spec.ts

@@ -553,4 +553,44 @@ describe('renderer: teleport', () => {
       `"<div>teleported</div>"`
     )
   })
+
+  // #9071
+  test('should render within the target element unique child element', async () => {
+    const root = document.createElement('div')
+
+    const show = ref(false)
+
+    const App = defineComponent({
+      setup() {
+        return () => {
+          return show.value
+            ? h(Teleport, { to: root }, h('div', 'Teleported'))
+            : h('div', 'foo')
+        }
+      }
+    })
+
+    domRender(h(App), root)
+
+    expect(root.innerHTML).toMatchInlineSnapshot('"<div>foo</div>"')
+
+    show.value = true
+    await nextTick()
+
+    expect(root.innerHTML).toMatchInlineSnapshot(
+      '"<!--teleport start--><!--teleport end--><div>Teleported</div>"'
+    )
+
+    show.value = false
+    await nextTick()
+
+    expect(root.innerHTML).toMatchInlineSnapshot('"<div>foo</div>"')
+
+    show.value = true
+    await nextTick()
+
+    expect(root.innerHTML).toMatchInlineSnapshot(
+      '"<!--teleport start--><!--teleport end--><div>Teleported</div>"'
+    )
+  })
 })

packages/runtime-dom/src/nodeOps.ts

@@ -8,7 +8,9 @@ const templateContainer = doc && /*#__PURE__*/ doc.createElement('template')
 
 export const nodeOps: Omit<RendererOptions<Node, Element>, 'patchProp'> = {
   insert: (child, parent, anchor) => {
-    parent.insertBefore(child, anchor || null)
+    // #9071
+    anchor = anchor && anchor.parentNode === parent ? anchor : null
+    parent.insertBefore(child, anchor)
   },
 
   remove: child => {